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Zhang J, Liu Y, Zhi X, Xu L, Tao J, Cui D, Liu TF. Tryptophan catabolism via the kynurenine pathway regulates infection and inflammation: from mechanisms to biomarkers and therapies. Inflamm Res 2024; 73:979-996. [PMID: 38592457 DOI: 10.1007/s00011-024-01878-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/24/2024] [Accepted: 03/27/2024] [Indexed: 04/10/2024] Open
Abstract
BACKGROUND L-Tryptophan (L-Trp), an essential amino acid, is the only amino acid whose level is regulated specifically by immune signals. Most proportions of Trp are catabolized via the kynurenine (Kyn) pathway (KP) which has evolved to align the food availability and environmental stimulation with the host pathophysiology and behavior. Especially, the KP plays an indispensable role in balancing the immune activation and tolerance in response to pathogens. SCOPE OF REVIEW In this review, we elucidate the underlying immunological regulatory network of Trp and its KP-dependent catabolites in the pathophysiological conditions by participating in multiple signaling pathways. Furthermore, the KP-based regulatory roles, biomarkers, and therapeutic strategies in pathologically immune disorders are summarized covering from acute to chronic infection and inflammation. MAJOR CONCLUSIONS The immunosuppressive effects dominate the functions of KP induced-Trp depletion and KP-produced metabolites during infection and inflammation. However, the extending minor branches from the KP are not confined to the immune tolerance, instead they go forward to various functions according to the specific condition. Nevertheless, persistent efforts should be made before the clinical use of KP-based strategies to monitor and cure infectious and inflammatory diseases.
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Affiliation(s)
- Jingpu Zhang
- Scientific Research Center, Shanghai Public Health Clinical Center, Fudan University, 2901 Caolang Highway, Shanghai, 201508, People's Republic of China.
| | - Yanlei Liu
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Xiao Zhi
- Shanghai Institute of Virology, Shanghai Jiao Tong University School of Medicine, 227 South Chongqing Road, Shanghai, 200025, People's Republic of China
| | - Li Xu
- Scientific Research Center, Shanghai Public Health Clinical Center, Fudan University, 2901 Caolang Highway, Shanghai, 201508, People's Republic of China
| | - Jie Tao
- Scientific Research Center, Shanghai Public Health Clinical Center, Fudan University, 2901 Caolang Highway, Shanghai, 201508, People's Republic of China
| | - Daxiang Cui
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China
| | - Tie Fu Liu
- Scientific Research Center, Shanghai Public Health Clinical Center, Fudan University, 2901 Caolang Highway, Shanghai, 201508, People's Republic of China.
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Ardizzone CM, Taylor CM, Toh E, Lillis RA, Elnaggar JH, Lammons JW, Mott PD, Duffy EL, Shen L, Quayle AJ. Association of Chlamydia trachomatis burden with the vaginal microbiota, bacterial vaginosis, and metronidazole treatment. Front Cell Infect Microbiol 2023; 13:1289449. [PMID: 38149008 PMCID: PMC10750252 DOI: 10.3389/fcimb.2023.1289449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 11/21/2023] [Indexed: 12/28/2023] Open
Abstract
Bacterial vaginosis (BV), a dysbiosis of the vaginal microbiota, is a common coinfection with Chlamydia trachomatis (Ct), and BV-associated bacteria (BVAB) and their products have been implicated in aiding Ct evade natural immunity. Here, we determined if a non-optimal vaginal microbiota was associated with a higher genital Ct burden and if metronidazole, a standard treatment for BV, would reduce Ct burden or aid in natural clearance of Ct infection. Cervicovaginal samples were collected from women at enrollment and, if testing positive for Ct infection, at a follow-up visit approximately one week later. Cervical Ct burden was assessed by inclusion forming units (IFU) and Ct genome copy number (GCN), and 16S rRNA gene sequencing was used to determine the composition of the vaginal microbiota. We observed a six-log spectrum of IFU and an eight-log spectrum of GCN in our study participants at their enrollment visit, but BV, as indicated by Amsel's criteria, Nugent scoring, or VALENCIA community state typing, did not predict infectious and total Ct burden, although IFU : GCN increased with Amsel and Nugent scores and in BV-like community state types. Ct burden was, however, associated with the abundance of bacterial species in the vaginal microbiota, negatively with Lactobacillus crispatus and positively with Prevotella bivia. Women diagnosed with BV were treated with metronidazole, and Ct burden was significantly reduced in those who resolved BV with treatment. A subset of women naturally cleared Ct infection in the interim, typified by low Ct burden at enrollment and resolution of BV. Abundance of many BVAB decreased, and Lactobacillus increased, in response to metronidazole treatment, but no changes in abundances of specific vaginal bacteria were unique to women who spontaneously cleared Ct infection.
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Affiliation(s)
- Caleb M. Ardizzone
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Christopher M. Taylor
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Evelyn Toh
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Rebecca A. Lillis
- Department of Medicine, Section of Infectious Diseases, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Jacob H. Elnaggar
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - John W. Lammons
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Patricia Dehon Mott
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Emily L. Duffy
- Department of Medicine, Section of Infectious Diseases, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Li Shen
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Alison J. Quayle
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
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3
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Riffaud CM, Rucks EA, Ouellette SP. Persistence of obligate intracellular pathogens: alternative strategies to overcome host-specific stresses. Front Cell Infect Microbiol 2023; 13:1185571. [PMID: 37284502 PMCID: PMC10239878 DOI: 10.3389/fcimb.2023.1185571] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/05/2023] [Indexed: 06/08/2023] Open
Abstract
In adapting to the intracellular niche, obligate intracellular bacteria usually undergo a reduction of genome size by eliminating genes not needed for intracellular survival. These losses can include, for example, genes involved in nutrient anabolic pathways or in stress response. Living inside a host cell offers a stable environment where intracellular bacteria can limit their exposure to extracellular effectors of the immune system and modulate or outright inhibit intracellular defense mechanisms. However, highlighting an area of vulnerability, these pathogens are dependent on the host cell for nutrients and are very sensitive to conditions that limit nutrient availability. Persistence is a common response shared by evolutionarily divergent bacteria to survive adverse conditions like nutrient deprivation. Development of persistence usually compromises successful antibiotic therapy of bacterial infections and is associated with chronic infections and long-term sequelae for the patients. During persistence, obligate intracellular pathogens are viable but not growing inside their host cell. They can survive for a long period of time such that, when the inducing stress is removed, reactivation of their growth cycles resumes. Given their reduced coding capacity, intracellular bacteria have adapted different response mechanisms. This review gives an overview of the strategies used by the obligate intracellular bacteria, where known, which, unlike model organisms such as E. coli, often lack toxin-antitoxin systems and the stringent response that have been linked to a persister phenotype and amino acid starvation states, respectively.
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Tryptophan Availability during Persistence of Chlamydia trachomatis Directly Impacts Expression of Chlamydial Cell Division Proteins. Infect Immun 2023; 91:e0051322. [PMID: 36645295 PMCID: PMC9933654 DOI: 10.1128/iai.00513-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Chlamydia is an obligate intracellular pathogen with a highly reduced genome devoid of major stress response genes like relA and spoT, which mediate the stringent response. Interestingly, as an intracellular bacterium dependent on its host for nutrients and as a tryptophan (Trp) auxotroph, Chlamydia is very sensitive to Trp starvation, which is induced in vivo by the host cytokine interferon-γ. In response to Trp starvation, Chlamydia enters a viable but nonreplicating state called persistence. A major characteristic of chlamydial persistence is a block in cell division. We hypothesized that cell division is blocked during persistence by the inability to translate Trp-rich cell division proteins. To test this, we first investigated the translation of various cell division proteins under Trp starvation conditions using inducible expression strains. We observed that the Trp-poor protein MurG and the Trp-neutral protein FtsL were still expressed during persistence, while the expression of the Trp-rich proteins Pbp2, RodA, FtsI/Pbp3, and MraY was significantly reduced. As proof of concept for our hypothesis, we compared expression of a wild-type and mutant isoform of RodZ in which its four Trp codons were mutated. These experiments demonstrated that decreased expression of RodZ during persistence was reversed when no Trp was present in the protein, thus directly linking its expression to its Trp content. Together, these experiments indicate that specific cell division proteins are not produced during persistence. For the first time, our data provide a mechanism that explains the inhibition of cell division during chlamydial persistence mediated by Trp starvation.
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Hou C, Jin Y, Wu H, Li P, Liu L, Zheng K, Wang C. Alternative strategies for Chlamydia treatment: Promising non-antibiotic approaches. Front Microbiol 2022; 13:987662. [PMID: 36504792 PMCID: PMC9727249 DOI: 10.3389/fmicb.2022.987662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 11/04/2022] [Indexed: 11/24/2022] Open
Abstract
Chlamydia is an obligate intracellular bacterium where most species are pathogenic and infectious, causing various infectious diseases and complications in humans and animals. Antibiotics are often recommended for the clinical treatment of chlamydial infections. However, extensive research has shown that antibiotics may not be sufficient to eliminate or inhibit infection entirely and have some potential risks, including antibiotic resistance. The impact of chlamydial infection and antibiotic misuse should not be underestimated in public health. This study explores the possibility of new therapeutic techniques, including a review of recent studies on preventing and suppressing chlamydial infection by non-antibiotic compounds.
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Affiliation(s)
- Chen Hou
- School of Basic Medicine, Hengyang Medical College, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Yingqi Jin
- School of Basic Medicine, Hengyang Medical College, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Hua Wu
- Department of Clinical Laboratory, Affiliated Hengyang Hospital of Southern Medical University, Hengyang Central Hospital, Hengyang, China
| | - Pengyi Li
- School of Basic Medicine, Hengyang Medical College, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Longyun Liu
- School of Basic Medicine, Hengyang Medical College, Institute of Pathogenic Biology, University of South China, Hengyang, China
| | - Kang Zheng
- Department of Clinical Laboratory, Affiliated Hengyang Hospital of Southern Medical University, Hengyang Central Hospital, Hengyang, China,*Correspondence: Kang Zheng
| | - Chuan Wang
- School of Basic Medicine, Hengyang Medical College, Institute of Pathogenic Biology, University of South China, Hengyang, China,Chuan Wang
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6
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Wang L, Hou Y, Yuan H, Chen H. The role of tryptophan in Chlamydia trachomatis persistence. Front Cell Infect Microbiol 2022; 12:931653. [PMID: 35982780 PMCID: PMC9378776 DOI: 10.3389/fcimb.2022.931653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/14/2022] [Indexed: 11/26/2022] Open
Abstract
Chlamydia trachomatis (C. trachomatis) is the most common etiological agent of bacterial sexually transmitted infections (STIs) and a worldwide public health issue. The natural course with C. trachomatis infection varies widely between individuals. Some infections clear spontaneously, others can last for several months or some individuals can become reinfected, leading to severe pathological damage. Importantly, the underlying mechanisms of C. trachomatis infection are not fully understood. C. trachomatis has the ability to adapt to immune response and persist within host epithelial cells. Indoleamine-2,3-dioxygenase (IDO) induced by interferon-gamma (IFN-γ) degrades the intracellular tryptophan pool, to which C. trachomatis can respond by converting to a non-replicating but viable state. C. trachomatis expresses and encodes for the tryptophan synthase (TS) genes (trpA and trpB) and tryptophan repressor gene (trpR). Multiple genes interact to regulate tryptophan synthesis from exogenous indole, and persistent C. trachomatis can recover its infectivity by converting indole into tryptophan. In this review, we discuss the characteristics of chlamydial infections, biosynthesis and regulation of tryptophan, the relationship between tryptophan and C. trachomatis, and finally, the links between the tryptophan/IFN-γ axis and C. trachomatis persistence.
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Affiliation(s)
- Li Wang
- The First School of Clinical Medicine, Chenzhou No.1 People’s Hospital, Southern Medical University, Guangzhou, China
- Department of Clinical Microbiology Laboratory, Chenzhou No.1 People’s Hospital, Chenzhou, China
| | - YingLan Hou
- The First School of Clinical Medicine, Chenzhou No.1 People’s Hospital, Southern Medical University, Guangzhou, China
- Department of Clinical Microbiology Laboratory, Chenzhou No.1 People’s Hospital, Chenzhou, China
| | - HongXia Yuan
- The First School of Clinical Medicine, Chenzhou No.1 People’s Hospital, Southern Medical University, Guangzhou, China
- Department of Clinical Microbiology Laboratory, Chenzhou No.1 People’s Hospital, Chenzhou, China
| | - Hongliang Chen
- The First School of Clinical Medicine, Chenzhou No.1 People’s Hospital, Southern Medical University, Guangzhou, China
- Department of Clinical Microbiology Laboratory, Chenzhou No.1 People’s Hospital, Chenzhou, China
- *Correspondence: Hongliang Chen,
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Vection S, O'Callaghan D, Keriel A. CD98hc in host-pathogen interactions: roles of the multifunctional host protein during infections. FEMS Microbiol Rev 2022; 46:6590039. [PMID: 35595511 DOI: 10.1093/femsre/fuac023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022] Open
Abstract
The eukaryotic protein CD98hc (also known as 4F2, FRP-1 or SLC3A2) is a membrane glycoprotein and one of the heavy chains of the family of heterodimeric amino acids transporters. It can associate with any of 6 different light chains to form distinct amino acid transporters. CD98hc is also involved in mediation of intracellular integrin signaling. Besides its physiological roles in the development of the placenta and the immune system, CD98hc is important during pathological processes such as tumorigenesis and host-pathogen interaction. Since its first identification as Fusion Regulatory Protein 1 regulating cell fusion in cells infected by the Newcastle disease virus, CD98hc has been reported to be mediating many viral, apicomplexan, and bacterial infectious processes. In this review we describe the role of CD98hc and its associated light chains in bacterial, apicomplexan, and viral pathogenesis. We also discuss the consequences of infection on the expression and localization of these proteins. The identification of the cellular processes in which CD98hc is involved during pathogenesis highlights the key role of this host protein in infectious diseases.
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Affiliation(s)
- Sonia Vection
- VBIC, U1047 INSERM, Université de Montpellier, Nîmes, France.,Centre National de Référence des Brucella, Laboratoire de Microbiologie, CHU de Nîmes, Nîmes, France
| | - David O'Callaghan
- VBIC, U1047 INSERM, Université de Montpellier, Nîmes, France.,Centre National de Référence des Brucella, Laboratoire de Microbiologie, CHU de Nîmes, Nîmes, France
| | - Anne Keriel
- VBIC, U1047 INSERM, Université de Montpellier, Nîmes, France.,Centre National de Référence des Brucella, Laboratoire de Microbiologie, CHU de Nîmes, Nîmes, France
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8
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Sharma J, Gupta K, Schwebke JR, Geisler WM, Muzny CA. Association of Bacterial Vaginosis With Higher Vaginal Indole Levels. Sex Transm Dis 2022; 49:e53-e55. [PMID: 34561371 DOI: 10.1097/olq.0000000000001564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ABSTRACT We adapted a simple hydroxylamine-based indole assay to detect indole from stored vaginal swab specimens from women with and without bacterial vaginosis (BV). Women with BV had significantly higher vaginal indole levels compared with women without BV (6451.5 vs 5632.4 μM; P = 0.01), suggesting that indole-producing bacteria are a component of BV.
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Affiliation(s)
- Jyoti Sharma
- From the Division of Infectious Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
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9
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Abstract
Pulmonary granulomas are widely considered the epicenters of the immune response to Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). Recent animal studies have revealed factors that either promote or restrict TB immunity within granulomas. These models, however, typically ignore the impact of preexisting immunity on cellular organization and function, an important consideration because most TB probably occurs through reinfection of previously exposed individuals. Human postmortem research from the pre-antibiotic era showed that infections in Mtb-naïve individuals (primary TB) versus those with prior Mtb exposure (postprimary TB) have distinct pathologic features. We review recent animal findings in TB granuloma biology, which largely reflect primary TB. We also discuss our current understanding of postprimary TB lesions, about which much less is known. Many knowledge gaps remain, particularly regarding how preexisting immunity shapes granuloma structure and local immune responses at Mtb infection sites. Expected final online publication date for the Annual Review of Immunology, Volume 40 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Sara B. Cohen
- Seattle Children's Research Institute, Seattle, Washington, USA
| | - Benjamin H. Gern
- Seattle Children's Research Institute, Seattle, Washington, USA
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Kevin B. Urdahl
- Seattle Children's Research Institute, Seattle, Washington, USA
- Department of Pediatrics, University of Washington, Seattle, Washington, USA
- Department of Immunology, University of Washington, Seattle, Washington, USA
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10
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Codon-Dependent Transcriptional Changes in Response to Tryptophan Limitation in the Tryptophan Auxotrophic Pathogens Chlamydia trachomatis and Streptococcus pyogenes. mSystems 2021; 6:e0126921. [PMID: 34904862 PMCID: PMC8670374 DOI: 10.1128/msystems.01269-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chlamydia trachomatis and Streptococcus pyogenes are among the most prevalent bacterial pathogens of humans. Interestingly, both pathogens are tryptophan (Trp) auxotrophs and must acquire this essential amino acid from their environment. For Chlamydia, an obligate intracellular bacterium, this means scavenging Trp from the host cell in which they reside. For Streptococcus, a primarily extracellular bacterium, this means scavenging Trp from the local environment. In the course of a natural immune response, both pathogens can be exposed to Trp-limiting conditions through the action of the interferon gamma-inducible IDO1 enzyme, which catabolizes Trp to N-formylkynurenine. How these pathogens respond to Trp starvation is incompletely understood. However, we have previously demonstrated that genes enriched in Trp codons were preferentially transcribed in C. pneumoniae during Trp limitation. Chlamydia, but not Streptococcus, lacks a stringent response, which is a global regulon activated by uncharged tRNAs binding in the A site of the ribosome. We hypothesized that the chlamydial response to Trp limitation is a consequence of lacking a stringent response. To test this, we compared global transcription profiles of C. trachomatis to both wild-type and stringent response mutant strains of Streptococcus during Trp starvation. We observed that both Trp auxotrophs respond with codon-dependent changes in their transcriptional profiles that correlate with Trp codon content but not transcript stability. Importantly, the stringent response had no impact on these transcriptional changes, suggesting an evolutionarily conserved adaptation to Trp starvation. Therefore, we have revealed a novel response of Trp auxotrophic pathogens in response to Trp starvation. IMPORTANCEChlamydia trachomatis and Streptococcus pyogenes are important pathogens of humans. Interestingly, both are auxotrophic for tryptophan and acquire this essential amino acid from the host environment. However, part of the host defense against pathogens includes the degradation of tryptophan pools. Therefore, Chlamydia and Streptococcus are particularly susceptible to tryptophan starvation. Most model bacteria respond to amino acid starvation by using a global regulon called the stringent response. However, Chlamydia lacks a stringent response. Here, we investigated the chlamydial response to tryptophan starvation and compared it to both wild-type and stringent response mutant strains of S. pyogenes to determine what role a functional stringent response plays during tryptophan starvation in these pathogens. We determined that both of these pathogens respond to tryptophan starvation by increasing transcription of tryptophan codon-rich genes. This effect was not dependent on the stringent response and highlights a previously unrecognized and potentially evolutionarily conserved mechanism for surviving tryptophan starvation.
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Correlation Analysis between Gut Microbiota and Metabolites in Children with Systemic Lupus Erythematosus. J Immunol Res 2021; 2021:5579608. [PMID: 34341764 PMCID: PMC8325587 DOI: 10.1155/2021/5579608] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/30/2021] [Accepted: 07/02/2021] [Indexed: 12/14/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune-mediated diffuse connective tissue disease characterized by immune inflammation with an unclear aetiology and pathogenesis. This work profiled the intestinal flora and faecal metabolome of patients with SLE using 16S RNA sequencing and gas chromatography-mass spectrometry (GC-MS). We identified unchanged alpha diversity and partially altered beta diversity of the intestinal flora. Another important finding was the increase in Proteobacteria and Enterobacteriales and the decrease in Ruminococcaceae among SLE patients. For metabolites, amino acids and short-chain fatty acids were enriched when long-chain fatty acids were downregulated in SLE faecal samples. KEGG analysis showed the significance of the protein digestion and absorption pathway, and association analysis revealed the key role of 3-phenylpropanoic acid and Sphingomonas. Sphingomonas were reported to be less abundant in healthy periodontal sites of SLE patients than in those of HCs, indicating transmission of oral species to the gut. This study contributes to the understanding of the pathogenesis of SLE disease from the perspective of intestinal microorganisms, explains the pathogenesis of SLE, and serves as a basis for exploring potential treatments for the disease.
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12
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Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL. Sci Rep 2021; 11:7730. [PMID: 33833328 PMCID: PMC8032716 DOI: 10.1038/s41598-021-87259-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/26/2021] [Indexed: 01/22/2023] Open
Abstract
The pigment cell-specific protein PMEL forms a functional amyloid matrix in melanosomes onto which the pigment melanin is deposited. The amyloid core consists of a short proteolytic fragment, which we have termed the core-amyloid fragment (CAF) and perhaps additional parts of the protein, such as the PKD domain. A highly O-glycosylated repeat (RPT) domain also derived from PMEL proteolysis associates with the amyloid and is necessary to establish the sheet-like morphology of the assemblies. Excluded from the aggregate is the regulatory N-terminus, which nevertheless must be linked in cis to the CAF in order to drive amyloid formation. The domain is then likely cleaved away immediately before, during, or immediately after the incorporation of a new CAF subunit into the nascent amyloid. We had previously identified a 21 amino acid long region, which mediates the regulatory activity of the N-terminus towards the CAF. However, many mutations in the respective segment caused misfolding and/or blocked PMEL export from the endoplasmic reticulum, leaving their phenotype hard to interpret. Here, we employ a saturating mutagenesis approach targeting the motif at single amino acid resolution. Our results confirm the critical nature of the PMEL N-terminal region and identify several residues essential for PMEL amyloidogenesis.
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13
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Zhao H, Yu C, He C, Mei C, Liao A, Huang D. The Immune Characteristics of the Epididymis and the Immune Pathway of the Epididymitis Caused by Different Pathogens. Front Immunol 2020; 11:2115. [PMID: 33117332 PMCID: PMC7561410 DOI: 10.3389/fimmu.2020.02115] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/05/2020] [Indexed: 01/26/2023] Open
Abstract
The epididymis is an important male accessory sex organ where sperm motility and fertilization ability develop. When spermatozoa carrying foreign antigens enter the epididymis, the epididymis shows "immune privilege" to tolerate them. It is well-known that a tolerogenic environment exists in the caput epididymis, while pro-inflammatory circumstances prefer the cauda epididymis. This meticulously regulated immune environment not only protects spermatozoa from autoimmunity but also defends spermatozoa against pathogenic damage. Epididymitis is one of the common causes of male infertility. Up to 40% of patients suffer from permanent oligospermia or azoospermia. This is related to the immune characteristics of the epididymis itself. Moreover, epididymitis induced by different pathogenic microbial infections has different characteristics. This article elaborates on the distribution and immune response characteristics of epididymis immune cells, the role of epididymis epithelial cells (EECs), and the epididymis defense against different pathogenic infections (such as uropathogenic Escherichia coli, Chlamydia trachomatis, and viruses to provide therapeutic approaches for epididymitis and its subsequent fertility problems.
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Affiliation(s)
- Hu Zhao
- Department of Human Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Caiqian Yu
- Department of Human Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chunyu He
- Institute of Reproduction Health Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chunlei Mei
- Institute of Reproduction Health Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Aihua Liao
- Institute of Reproduction Health Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Donghui Huang
- Institute of Reproduction Health Research, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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14
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Yan R, Jiang H, Gu S, Feng N, Zhang N, Lv L, Liu F. Fecal Metabolites Were Altered, Identified as Biomarkers and Correlated With Disease Activity in Patients With Systemic Lupus Erythematosus in a GC-MS-Based Metabolomics Study. Front Immunol 2020; 11:2138. [PMID: 33013903 PMCID: PMC7511511 DOI: 10.3389/fimmu.2020.02138] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022] Open
Abstract
Gut metabolites are products of the crosstalk between microbes and their host and play an important role in the occurrence, development, diagnosis, and treatment of autoimmune diseases. This work profiled the fecal metabolome of patients with systemic lupus erythematosus (SLE) using gas chromatography-mass spectrometry (GC-MS) and analyzed the potential roles of metabolites in the diagnosis and development of SLE. Fecal sample from 29 SLE patients without any other diseases and 30 healthy controls (HCs) were analyzed by metabolomics profiling. All participants took no antibiotics in the month before sampling and clinical data collecting. The metabolome profiles of patients with SLE and HCs were significantly different. Thirty fecal metabolites, such as deoxycholic acid, erucamide, L-tryptophan and putrescine, were significantly enriched, while nine metabolites, such as glyceric acid, γ-tocopherol, (Z)-13-octadecenoic acid and 2,4-di-tert-butylphenol, were depleted in SLE patients vs. HCs. The areas under the curve (AUCs) of L-valine, pyrimidine, erucamide, and L-leucine during ROC analysis were 0.886, 0.833, 0.829, and 0.803, indicating their good diagnostic potential. Moreover, the combination of L-valine, erucamide and 2,4-di-tert-butylphenol gave an AUC of 0.959. SLE-altered metabolites were significantly located in 28 pathways, such as ABC transporters (p = 3.40E-13) and aminoacyl-tRNA biosynthesis (p = 2.11E-12). Furthermore, SLE-altered fecal metabolites were closely correlated with SLE indicators, e.g., L-tryptophan was positively correlated with the SLEDAI-2K (p = 0.007). Our results suggest that the SLE fecal metabolome is closely associated with the occurrence and development of SLE and is of great diagnostic value.
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Affiliation(s)
- Ren Yan
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Huiyong Jiang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Silan Gu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Ninghan Feng
- Department of Urology, Affiliated Wuxi No.2 People's Hospital, Nanjing Medical University, Wuxi, China
| | - Nan Zhang
- Department of Urology, Affiliated Wuxi No.2 People's Hospital, Nanjing Medical University, Wuxi, China
| | - Longxian Lv
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Fengping Liu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Wuxi School of Medicine, Jiangnan University, Wuxi, China
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15
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McQueen BE, Kiatthanapaiboon A, Fulcher ML, Lam M, Patton K, Powell E, Kollipara A, Madden V, Suchland RJ, Wyrick P, O'Connell CM, Reidel B, Kesimer M, Randell SH, Darville T, Nagarajan UM. Human Fallopian Tube Epithelial Cell Culture Model To Study Host Responses to Chlamydia trachomatis Infection. Infect Immun 2020; 88:e00105-20. [PMID: 32601108 PMCID: PMC7440757 DOI: 10.1128/iai.00105-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/23/2020] [Indexed: 12/20/2022] Open
Abstract
Chlamydia trachomatis infection of the human fallopian tubes can lead to damaging inflammation and scarring, ultimately resulting in infertility. To study the human cellular responses to chlamydial infection, researchers have frequently used transformed cell lines that can have limited translational relevance. We developed a primary human fallopian tube epithelial cell model based on a method previously established for culture of primary human bronchial epithelial cells. After protease digestion and physical dissociation of excised fallopian tubes, epithelial cell precursors were expanded in growth factor-containing medium. Expanded cells were cryopreserved to generate a biobank of cells from multiple donors and cultured at an air-liquid interface. Culture conditions stimulated cellular differentiation into polarized mucin-secreting and multiciliated cells, recapitulating the architecture of human fallopian tube epithelium. The polarized and differentiated cells were infected with a clinical isolate of C. trachomatis, and inclusions containing chlamydial developmental forms were visualized by fluorescence and electron microscopy. Apical secretions from infected cells contained increased amounts of proteins associated with chlamydial growth and replication, including transferrin receptor protein 1, the amino acid transporters SLC3A2 and SLC1A5, and the T-cell chemoattractants CXCL10, CXCL11, and RANTES. Flow cytometry revealed that chlamydial infection induced cell surface expression of T-cell homing and activation proteins, including ICAM-1, VCAM-1, HLA class I and II, and interferon gamma receptor. This human fallopian tube epithelial cell culture model is an important tool with translational potential for studying cellular responses to Chlamydia and other sexually transmitted pathogens.
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Affiliation(s)
- Bryan E McQueen
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina, USA
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Amy Kiatthanapaiboon
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - M Leslie Fulcher
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Mariam Lam
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Kate Patton
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Emily Powell
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Avinash Kollipara
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina, USA
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Victoria Madden
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Robert J Suchland
- University of Washington, Division of Allergy and Infectious Diseases, Department of Medicine, Seattle, Washington, USA
| | - Priscilla Wyrick
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Catherine M O'Connell
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Boris Reidel
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Mehmet Kesimer
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Scott H Randell
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Toni Darville
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina, USA
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Uma M Nagarajan
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina, USA
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
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16
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Inhibition of tRNA Synthetases Induces Persistence in Chlamydia. Infect Immun 2020; 88:IAI.00943-19. [PMID: 31964747 DOI: 10.1128/iai.00943-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 01/15/2020] [Indexed: 02/06/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections, and Chlamydia pneumoniae causes community-acquired respiratory infections. In vivo, the host immune system will release gamma interferon (IFN-γ) to combat infection. IFN-γ activates human cells to produce the tryptophan (Trp)-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO). Consequently, there is a reduction in cytosolic Trp in IFN-γ-activated host cells. In evolving to obligate intracellular dependence, Chlamydia has significantly reduced its genome size and content, as it relies on the host cell for various nutrients. Importantly, C. trachomatis and C. pneumoniae are Trp auxotrophs and are starved for this essential nutrient when the human host cell is exposed to IFN-γ. To survive this, chlamydiae enter an alternative developmental state referred to as persistence. Chlamydial persistence is characterized by a halt in the division cycle, aberrant morphology, and, in the case of IFN-γ-induced persistence, Trp codon-dependent changes in transcription. We hypothesize that these changes in transcription are dependent on the particular amino acid starvation state. To investigate the chlamydial response mechanisms acting when other amino acids become limiting, we tested the efficacy of prokaryote-specific tRNA synthetase inhibitors, indolmycin and AN3365, to mimic starvation of Trp and leucine, respectively. We show that these drugs block chlamydial growth and induce changes in morphology and transcription consistent with persistence. Importantly, growth inhibition was reversed when the compounds were removed from the medium. With these data, we find that indolmycin and AN3365 are valid tools that can be used to mimic the persistent state independently of IFN-γ.
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17
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Chlamydia psittaci-Infected Dendritic Cells Communicate with NK Cells via Exosomes To Activate Antibacterial Immunity. Infect Immun 2019; 88:IAI.00541-19. [PMID: 31658957 DOI: 10.1128/iai.00541-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 10/21/2019] [Indexed: 12/31/2022] Open
Abstract
Dendritic cells (DCs) and natural killer (NK) cells are critically involved in the early response against various bacterial microbes. Functional activation of infected DCs and NK cell-mediated gamma interferon (IFN-γ) secretion essentially contribute to the protective immunity against Chlamydia How DCs and NK cells cooperate during the antichlamydial response is not fully understood. Therefore, in the present study, we investigated the functional interplay between Chlamydia-infected DCs and NK cells. Our biochemical and cell biological experiments show that Chlamydia psittaci-infected DCs display enhanced exosome release. We find that such extracellular vesicles (referred to as dexosomes) do not contain infectious bacterial material but strongly induce IFN-γ production by NK cells. This directly affects C. psittaci growth in infected target cells. Furthermore, NK cell-released IFN-γ in cooperation with tumor necrosis factor alpha (TNF-α) and/or dexosomes augments apoptosis of both noninfected and infected epithelial cells. Thus, the combined effect of dexosomes and proinflammatory cytokines restricts C. psittaci growth and attenuates bacterial subversion of apoptotic host cell death. In conclusion, this provides new insights into the functional cooperation between DCs, dexosomes, and NK cells in the early steps of antichlamydial defense.
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18
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Lizárraga D, Carver S, Timms P. Navigating to the most promising directions amid complex fields of vaccine development: a chlamydial case study. Expert Rev Vaccines 2019; 18:1323-1337. [PMID: 31773996 DOI: 10.1080/14760584.2019.1698954] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Background: Vaccine-development research is proliferating making it difficult to determine the most promising vaccine candidates. Exemplary of this problem is vaccine development against Chlamydia, a pathogen of global public health and financial importance.Methods: We systematically extracted data from studies that included chlamydial load or host immune parameter measurements, estimating 4,453 standardized effect sizes between control and chlamydial immunization experimental groups.Results: Chlamydial immunization studies most often used (78%) laboratory mouse models. Depending on chlamydial species, single and multiple recombinant protein, viral and bacterial vectors, dendritic transfer, and dead whole pathogen were most effective at reducing chlamydial load. Immunization-driven decrease in chlamydial load was associated with increases in IFNg, IgA, IgG1, and IgG2a. Using data from individual studies, the magnitude of IgA and IgG2a increase was correlated with chlamydial load reduction. IFNg also showed this pattern for C. trachomatis, but not for C. muridarum. We also reveal the chlamydial vaccine development field to be highly bias toward studies showing these effects, limiting lessons learned from negative results.Conclusions: Most murine immunizations against Chlamydia reduced chlamydial load and increased host immune parameters. These methods are novel for vaccine development and are critical in identifying trends where large quantities of literature exist.
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Affiliation(s)
- David Lizárraga
- School of Natural Sciences, University of Tasmania, Hobart, Australia.,School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Australia
| | - Scott Carver
- School of Natural Sciences, University of Tasmania, Hobart, Australia
| | - Peter Timms
- School of Science and Engineering, University of the Sunshine Coast, Sippy Downs, Australia
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19
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Adu-Gyamfi CG, Savulescu D, George JA, Suchard MS. Indoleamine 2, 3-Dioxygenase-Mediated Tryptophan Catabolism: A Leading Star or Supporting Act in the Tuberculosis and HIV Pas-de-Deux? Front Cell Infect Microbiol 2019; 9:372. [PMID: 31737575 PMCID: PMC6828849 DOI: 10.3389/fcimb.2019.00372] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 10/14/2019] [Indexed: 12/11/2022] Open
Abstract
Progression from latency to active Tuberculosis (TB) disease is mediated by incompletely understood host immune factors. The definitive characteristic of progressive human immunodeficiency virus (HIV) disease is a severe loss in number and function of T lymphocytes. Among the many possible mediators of T lymphocyte loss and ineffective function is the activity of the immune-modulatory enzyme indoleamine 2,3-dioxygenase (IDO). IDO is the rate-limiting enzyme converting tryptophan to kynurenine. IDO activity was initially recognized to mediate tolerance at the foeto-maternal interface. Recently, IDO activity has also been noted to play a critical role in immune tolerance to pathogens. Studies of host immune and metabolic mediators have found IDO activity significantly elevated in HIV and TB disease. In this review, we explore the link between IDO-mediated tryptophan catabolism and the presence of active TB disease in HIV-infected patients. We draw attention to increased IDO activity as a key factor marking the progression from latent to active TB disease in HIV-infected patients.
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Affiliation(s)
- Clement Gascua Adu-Gyamfi
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, Johannesburg, South Africa.,Department of Chemical Pathology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Dana Savulescu
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Jaya Anna George
- Department of Chemical Pathology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Melinda Shelley Suchard
- Centre for Vaccines and Immunology, National Institute for Communicable Diseases, Johannesburg, South Africa.,Department of Chemical Pathology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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20
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Graham M, Tzika AC, Mitchell SM, Liu X, Leonhardt RM. Repeat domain-associated O-glycans govern PMEL fibrillar sheet architecture. Sci Rep 2019; 9:6101. [PMID: 30988362 PMCID: PMC6465243 DOI: 10.1038/s41598-019-42571-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/06/2019] [Indexed: 12/20/2022] Open
Abstract
PMEL is a pigment cell-specific protein that forms a functional amyloid matrix in melanosomes. The matrix consists of well-separated fibrillar sheets on which the pigment melanin is deposited. Using electron tomography, we demonstrate that this sheet architecture is governed by the PMEL repeat (RPT) domain, which associates with the amyloid as an accessory proteolytic fragment. Thus, the RPT domain is dispensable for amyloid formation as such but shapes the morphology of the matrix, probably in order to maximize the surface area available for pigment adsorption. Although the primary amino acid sequence of the RPT domain differs vastly among various vertebrates, we show that it is a functionally conserved, interchangeable module. RPT domains of all species are predicted to be very highly O-glycosylated, which is likely the common defining feature of this domain. O-glycosylation is indeed essential for RPT domain function and the establishment of the PMEL sheet architecture. Thus, O-glycosylation, not amino acid sequence, appears to be the major factor governing the characteristic PMEL amyloid morphology.
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Affiliation(s)
- Morven Graham
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06519, USA
| | - Athanasia C Tzika
- Department of Genetics & Evolution, Laboratory of Artificial & Natural Evolution (LANE), Sciences III Building, 1211, Geneva, 4, Switzerland
| | - Susan M Mitchell
- Department of Immunobiology, Yale University School of Medicine, 300 Cedar Street, New Haven, CT, 06519, USA
| | - Xinran Liu
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06519, USA
| | - Ralf M Leonhardt
- Department of Immunobiology, Yale University School of Medicine, 300 Cedar Street, New Haven, CT, 06519, USA.
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21
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Valenzuela-Miranda D, Gallardo-Escárate C. Dual RNA-Seq Uncovers Metabolic Amino Acids Dependency of the Intracellular Bacterium Piscirickettsia salmonis Infecting Atlantic Salmon. Front Microbiol 2018; 9:2877. [PMID: 30542335 PMCID: PMC6277808 DOI: 10.3389/fmicb.2018.02877] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 11/09/2018] [Indexed: 12/14/2022] Open
Abstract
High-throughput sequencing technologies have offered the possibility to understand the complexity of the transcriptomic responses of an organism during a wide variety of biological scenarios, such as the case of pathogenic infections. Recently, the simultaneous sequencing of both pathogen and host transcriptomes (dual RNA-seq) during the infection has become a promising approach to uncover the complexity of the host-pathogen interactions. In this study, through a double rRNA depletion and RNA sequencing protocols, we simultaneously analyzed the transcriptome of the intracellular bacterium Piscirickettsia salmonis and its host the Atlantic salmon (Salmo salar) during the course of the infection. Beyond canonical host immune-related response and pathogen virulent factors, both bacteria and host displayed a large number of genes associated with metabolism and particularly related with the amino acid metabolism. Notably, genome-wide comparison among P. salmonis genomes and different fish pathogens genomes revealed a lack of the biosynthetic pathway for several amino acids such as valine, leucine, and isoleucine. To support this finding, in vitro experiments evidenced that when these amino acids are restricted the bacterial growth dynamics is significantly affected. However, this condition is phenotypically reversed when the amino acids are supplemented in the bacterial growth medium. Based on our results, a metabolic dependency of P. salmonis on S. salar amino acids is suggested, which could imply novel mechanisms of pathogenesis based on the capacity to uptake nutrients from the host. Overall, dual transcriptome sequencing leads to the understanding of host-pathogen interactions from a different perspective, beyond biological processes related to immunity.
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Affiliation(s)
| | - Cristian Gallardo-Escárate
- Laboratory of Biotechnology and Aquatic Genomics, Interdisciplinary Center for Aquaculture Research, University of Concepción, Concepción, Chile
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22
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Ibana JA, Sherchand SP, Fontanilla FL, Nagamatsu T, Schust DJ, Quayle AJ, Aiyar A. Chlamydia trachomatis-infected cells and uninfected-bystander cells exhibit diametrically opposed responses to interferon gamma. Sci Rep 2018; 8:8476. [PMID: 29855501 PMCID: PMC5981614 DOI: 10.1038/s41598-018-26765-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/18/2018] [Indexed: 12/13/2022] Open
Abstract
The intracellular bacterial pathogen, Chlamydia trachomatis, is a tryptophan auxotroph. Therefore, induction of the host tryptophan catabolizing enzyme, indoleamine-2,3-dioxgenase-1 (IDO1), by interferon gamma (IFNγ) is one of the primary protective responses against chlamydial infection. However, despite the presence of a robust IFNγ response, active and replicating C. trachomatis can be detected in cervical secretions of women. We hypothesized that a primary C. trachomatis infection may evade the IFNγ response, and that the protective effect of this cytokine results from its activation of tryptophan catabolism in bystander cells. To test this hypothesis, we developed a novel method to separate a pool of cells exposed to C. trachomatis into pure populations of live infected and bystander cells and applied this technique to distinguish between the effects of IFNγ on infected and bystander cells. Our findings revealed that the protective induction of IDO1 is suppressed specifically within primary infected cells because Chlamydia attenuates the nuclear import of activated STAT1 following IFNγ exposure, without affecting STAT1 levels or phosphorylation. Critically, the IFNγ-mediated induction of IDO1 activity is unhindered in bystander cells. Therefore, the IDO1-mediated tryptophan catabolism is functional in these cells, transforming these bystander cells into inhospitable hosts for a secondary C. trachomatis infection.
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Affiliation(s)
- Joyce A Ibana
- Immunopharmacology Research Laboratory, Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines.
| | - Shardulendra P Sherchand
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
| | - Francis L Fontanilla
- Immunopharmacology Research Laboratory, Institute of Biology, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines
| | - Takeshi Nagamatsu
- Department of Obstetrics and Gynecology, Faculty Medicine, University of Tokyo, Tokyo, Japan
| | - Danny J Schust
- Department of Obstetrics, Gynecology, and Women's Health, University of Missouri, Columbia, MO, 15276, USA
| | - Alison J Quayle
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
| | - Ashok Aiyar
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, 70112, USA
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23
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Arshad N, Cresswell P. Tumor-associated calreticulin variants functionally compromise the peptide loading complex and impair its recruitment of MHC-I. J Biol Chem 2018; 293:9555-9569. [PMID: 29769311 DOI: 10.1074/jbc.ra118.002836] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 05/10/2018] [Indexed: 12/22/2022] Open
Abstract
Major histocompatibility complex-I-β2m dimers (MHC-I) bind peptides derived from intracellular proteins, enabling the immune system to distinguish between normal cells and those expressing pathogen-derived or mutant proteins. The peptides bind to MHC-I in the endoplasmic reticulum (ER), and this binding is facilitated by the peptide loading complex (PLC), which contains calreticulin (CRT). CRT associates with MHC-I via a conserved glycan present on MHC-I and recruits it to the PLC for peptide binding. Somatic frameshift mutations in CRT (CRT-FS) drive the proliferation of a subset of myeloproliferative neoplasms, which are chronic blood tumors. All CRT-FS proteins have a C-terminal sequence lacking the normal ER-retention signal and possessing a net negative charge rather than the normal positive charge. We characterized the effect of CRT-FS on antigen presentation by MHC-I in human cells. Our results indicate that CRT-FS cannot mediate CRT's peptide loading function in the PLC. Cells lacking CRT exhibited reduced surface MHC-I levels, consistent with reduced binding of high-affinity peptides, and this was not reversed by CRT-FS expression. CRT-FS was secreted and not detectably associated with the PLC, leading to poor MHC-I recruitment, although CRT-FS could still associate with MHC-I in a glycan-dependent manner. The addition of an ER-retention sequence to CRT-FS restored its association with the PLC but did not rescue MHC-I recruitment or its surface expression, indicating that the CRT-FS mutants functionally compromise the PLC. MHC-I down-regulation permits tumor cells to evade immune surveillance, and these findings may therefore be relevant for designing effective immunotherapies for managing myeloproliferative neoplasms.
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Affiliation(s)
| | - Peter Cresswell
- From the Departments of Immunobiology and .,Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520-8011
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24
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Dunstan SJ, Caws M. Could omics unlock the secret of surviving tuberculous meningitis? THE LANCET. INFECTIOUS DISEASES 2018; 18:479-480. [PMID: 29398390 DOI: 10.1016/s1473-3099(18)30055-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 11/27/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Sarah J Dunstan
- Peter Doherty Institute for Infection and Immunity, University of Melbourne, Parkville, VIC 3010, Australia.
| | - Maxine Caws
- Liverpool School of Tropical Medicine, Liverpool, UK
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25
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Tryptophan catabolites along the indoleamine 2,3-dioxygenase pathway as a biological link between depression and cancer. Behav Pharmacol 2018. [DOI: 10.1097/fbp.0000000000000384] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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26
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Ren W, Rajendran R, Zhao Y, Tan B, Wu G, Bazer FW, Zhu G, Peng Y, Huang X, Deng J, Yin Y. Amino Acids As Mediators of Metabolic Cross Talk between Host and Pathogen. Front Immunol 2018. [PMID: 29535717 PMCID: PMC5835074 DOI: 10.3389/fimmu.2018.00319] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The interaction between host and pathogen decidedly shapes the outcome of an infection, thus understanding this interaction is critical to the treatment of a pathogen-induced infection. Although research in this area of cell biology has yielded surprising findings regarding interactions between host and pathogen, understanding of the metabolic cross talk between host and pathogen is limited. At the site of infection, host and pathogen share similar or identical nutritional substrates and generate common metabolic products, thus metabolic cross talk between host and pathogen could profoundly affect the pathogenesis of an infection. In this review, we present results of a recent discovery of a metabolic interaction between host and pathogen from an amino acid (AA) metabolism-centric point of view. The host depends on AA metabolism to support defensive responses against pathogens, while the pathogens modulate AA metabolism for its own advantage. Some AA, such as arginine, asparagine, and tryptophan, are central points of competition between the host and pathogen. Thus, a better understanding of AA-mediated metabolic cross talk between host and pathogen will provide insight into fruitful therapeutic approaches to manipulate and prevent progression of an infection.
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Affiliation(s)
- Wenkai Ren
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Ranjith Rajendran
- School of Medicine, College of Medical, Veterinary and Life Sciences (MVLS), University of Glasgow, Glasgow, United Kingdom
| | - Yuanyuan Zhao
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Bie Tan
- Laboratory of Animal Nutrition and Health and Key Laboratory of Agro-Ecology, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha, China
| | - Guoyao Wu
- Department of Animal Science, Texas A&M University, TAMU, College Station, TX, United States
| | - Fuller W Bazer
- Department of Animal Science, Texas A&M University, TAMU, College Station, TX, United States
| | - Guoqiang Zhu
- Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Yuanyi Peng
- Chongqing Key Laboratory of Forage & Herbivorce, College of Animal Science and Technology, Southwest University, Chongqing, China
| | | | - Jinping Deng
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yulong Yin
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China
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Genomewide Transcriptional Responses of Iron-Starved Chlamydia trachomatis Reveal Prioritization of Metabolic Precursor Synthesis over Protein Translation. mSystems 2018; 3:mSystems00184-17. [PMID: 29468197 PMCID: PMC5811630 DOI: 10.1128/msystems.00184-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/18/2018] [Indexed: 12/16/2022] Open
Abstract
By utilizing an experimental approach that monitors the immediate global response of Chlamydia trachomatis to iron starvation, clues to long-standing issues in Chlamydia biology are revealed, including how Chlamydia adapts to this stress. We determined that this pathogen initiates a transcriptional program that prioritizes replenishment of nutrient stores over replication, possibly in preparation for rapid growth once optimal iron levels are restored. Transcription of genes for biosynthesis of metabolic precursors was generally upregulated, while those involved in multiple steps of translation were downregulated. We also observed an increase in transcription of genes involved in DNA repair and neutralizing oxidative stress, indicating that Chlamydia employs an “all-or-nothing” strategy. Its small genome limits its ability to tailor a specific response to a particular stress. Therefore, the “all-or-nothing” strategy may be the most efficient way of surviving within the host, where the pathogen likely encounters multiple simultaneous immunological and nutritional insults. Iron is essential for growth and development of Chlamydia. Its long-term starvation in cultured mammalian cells leads to production of aberrant noninfectious chlamydial forms, also known as persistence. Immediate transcriptional responses to iron limitation have not been characterized, leaving a knowledge gap of how Chlamydia regulates its response to changes in iron availability. We used the fast-chelating agent 2,2′-bipyridyl (BPDL) to homogeneously starve Chlamydia trachomatis serovar L2 of iron, starting at 6 or 12 h postinfection. Immediate transcriptional responses were monitored after only 3 or 6 h of BPDL treatment, well before formation of aberrant Chlamydia. The first genomewide transcriptional response of C. trachomatis to iron starvation was subsequently determined utilizing RNA sequencing. Only 7% and 8% of the genome were differentially expressed in response to iron starvation at the early and middle stages of development, respectively. Biological pathway analysis revealed an overarching theme. Synthesis of macromolecular precursors (deoxynucleotides, amino acids, charged tRNAs, and acetyl coenzyme A [acetyl-CoA]) was upregulated, while energy-expensive processes (ABC transport and translation) were downregulated. A large fraction of differentially downregulated genes are involved in translation, including those encoding ribosome assembly and initiation and termination factors, which could be analogous to the translation downregulation triggered by stress in other prokaryotes during stringent responses. Additionally, transcriptional upregulation of DNA repair, oxidative stress, and tryptophan salvage genes reveals a possible coordination of responses to multiple antimicrobial and immunological insults. These responses of replicative-phase Chlamydia to iron starvation indicate a prioritization of survival over replication, enabling the pathogen to “stock the pantry” with ingredients needed for rapid growth once optimal iron levels are restored. IMPORTANCE By utilizing an experimental approach that monitors the immediate global response of Chlamydia trachomatis to iron starvation, clues to long-standing issues in Chlamydia biology are revealed, including how Chlamydia adapts to this stress. We determined that this pathogen initiates a transcriptional program that prioritizes replenishment of nutrient stores over replication, possibly in preparation for rapid growth once optimal iron levels are restored. Transcription of genes for biosynthesis of metabolic precursors was generally upregulated, while those involved in multiple steps of translation were downregulated. We also observed an increase in transcription of genes involved in DNA repair and neutralizing oxidative stress, indicating that Chlamydia employs an “all-or-nothing” strategy. Its small genome limits its ability to tailor a specific response to a particular stress. Therefore, the “all-or-nothing” strategy may be the most efficient way of surviving within the host, where the pathogen likely encounters multiple simultaneous immunological and nutritional insults.
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Finethy R, Coers J. Sensing the enemy, containing the threat: cell-autonomous immunity to Chlamydia trachomatis. FEMS Microbiol Rev 2018; 40:875-893. [PMID: 28201690 DOI: 10.1093/femsre/fuw027] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/31/2016] [Accepted: 07/01/2016] [Indexed: 01/01/2023] Open
Abstract
The bacterium Chlamydia trachomatis is the etiological agent of the most common sexually transmitted infection in North America and Europe. Medical complications resulting from genital C. trachomatis infections arise predominantly in women where the initial infections often remain asymptomatic and thus unrecognized. Untreated asymptomatic infections in women can ascend into the upper genital tract and establish persistence, ultimately resulting in extensive scarring of the reproductive organs, pelvic inflammatory disease, infertility and ectopic pregnancies. Previously resolved C. trachomatis infections fail to provide protective immune memory, and no effective vaccine against C. trachomatis is currently available. Critical determinants of the pathogenesis and immunogenicity of genital C. trachomatis infections are cell-autonomous immune responses. Cell-autonomous immunity describes the ability of an individual host cell to launch intrinsic immune circuits that execute the detection, containment and elimination of cell-invading pathogens. As an obligate intracellular pathogen C. trachomatis is constantly under attack by cell-intrinsic host defenses. Accordingly, C. trachomatis evolved to subvert and co-opt cell-autonomous immune pathways. This review will provide a critical summary of our current understanding of cell-autonomous immunity to C. trachomatis and its role in shaping host resistance, inflammation and adaptive immunity to genital C. trachomatis infections.
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Affiliation(s)
- Ryan Finethy
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Jörn Coers
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA.,Department of Immunology, Duke University Medical Center, Durham, NC, USA
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Abstract
Chlamydiae are bacterial pathogens that grow in vacuolar inclusions. Dendritic cells (DCs) disintegrate these compartments, thereby eliminating the microbes, through auto/xenophagy, which also promotes chlamydial antigen presentation via MHC I. Here, we show that TNF-α controls this pathway by driving cytosolic phospholipase (cPLA)2-mediated arachidonic acid (AA) production. AA then impairs mitochondrial function, which disturbs the development and integrity of these energy-dependent parasitic inclusions, while a simultaneous metabolic switch towards aerobic glycolysis promotes DC survival. Tubulin deacetylase/autophagy regulator HDAC6 associates with disintegrated inclusions, thereby further disrupting their subcellular localisation and stability. Bacterial remnants are decorated with defective mitochondria, mito-aggresomal structures, and components of the ubiquitin/autophagy machinery before they are degraded via mito-xenophagy. The mechanism depends on cytoprotective HSP25/27, the E3 ubiquitin ligase Parkin and HDAC6 and promotes chlamydial antigen generation for presentation on MHC I. We propose that this novel mito-xenophagic pathway linking innate and adaptive immunity is critical for effective DC-mediated anti-bacterial resistance.
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Venomics analyses of the skin secretion of Dermatonotus muelleri : Preliminary proteomic and metabolomic profiling. Toxicon 2017; 130:127-135. [DOI: 10.1016/j.toxicon.2017.02.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 11/17/2022]
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In vitro rescue of genital strains of Chlamydia trachomatis from interferon-γ and tryptophan depletion with indole-positive, but not indole-negative Prevotella spp. BMC Microbiol 2016; 16:286. [PMID: 27914477 PMCID: PMC5135834 DOI: 10.1186/s12866-016-0903-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/24/2016] [Indexed: 11/10/2022] Open
Abstract
Background The natural course of sexually transmitted infections caused by Chlamydia trachomatis varies between individuals. In addition to parasite and host effects, the vaginal microbiota might play a key role in the outcome of C. trachomatis infections. Interferon-gamma (IFN-γ), known for its anti-chlamydial properties, activates the expression of indoleamine 2,3-dioxygenase (IDO1) in epithelial cells, an enzyme that catabolizes the amino acid L- tryptophan into N-formylkynurenine, depleting the host cell’s pool of tryptophan. Although C. trachomatis is a tryptophan auxotroph, urogenital strains (but not ocular strains) have been shown in vitro to have the ability to produce tryptophan from indole using the tryptophan synthase (trpBA) gene. It has been suggested that indole producing bacteria from the vaginal microbiota could influence the outcome of Chlamydia infection. Results We used two in vitro models (treatment with IFN-γ or direct limitation of tryptophan), to study the effects of direct rescue by the addition of exogenous indole, or by the addition of culture supernatant from indole-positive versus indole-negative Prevotella strains, on the growth and infectivity of C. trachomatis. We found that only supernatants from the indole-positive strains, P. intermedia and P. nigrescens, were able to rescue tryptophan-starved C. trachomatis. In addition, we analyzed vaginal secretion samples to determine physiological indole concentrations. In spite of the complexity of vaginal secretions, we demonstrated that for some vaginal specimens with higher indole levels, there was a link to higher recovery of the Chlamydia under tryptophan-starved conditions, lending preliminary support to the critical role of the IFN-γ-tryptophan-indole axis in vivo. Conclusions Our data provide evidence for the ability of both exogenous indole as well as supernatant from indole producing bacteria such as Prevotella, to rescue genital C. trachomatis from tryptophan starvation. This adds weight to the hypothesis that the vaginal microbiota (particularly from women with lower levels of lactobacilli and higher levels of indole producing anaerobes) may be intrinsically linked to the outcome of chlamydial infections in some women. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0903-4) contains supplementary material, which is available to authorized users.
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Pettengill MA, Abdul-Sater A, Coutinho-Silva R, Ojcius DM. Danger signals, inflammasomes, and the intricate intracellular lives of chlamydiae. Biomed J 2016; 39:306-315. [PMID: 27884377 PMCID: PMC6138786 DOI: 10.1016/j.bj.2016.07.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 07/13/2016] [Indexed: 12/20/2022] Open
Abstract
Chlamydiae are obligate intracellular bacterial pathogens, and as such are sensitive to alterations in the cellular physiology of their hosts. Chlamydial infections often cause pathologic consequences due to prolonged localized inflammation. Considerable advances have been made in the last few years regarding our understanding of how two key inflammation-associated signaling pathways influence the biology of Chlamydia infections: inflammation regulating purinergic signaling pathways significantly impact intracellular chlamydial development, and inflammasome activation modulates both chlamydial growth and infection mediated pro-inflammatory cytokine production. We review here elements of both pathways, presenting the latest developments contributing to our understanding of how chlamydial infections are influenced by inflammasomes and purinergic signaling.
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Affiliation(s)
| | - Ali Abdul-Sater
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Robson Coutinho-Silva
- Laboratory of Immunophysiology, Carlos Chagas Filho Biophysics Institute of the Federal University of Rio de Janeiro, Brazil
| | - David M Ojcius
- Laboratory of Immunophysiology, Carlos Chagas Filho Biophysics Institute of the Federal University of Rio de Janeiro, Brazil; Department of Biomedical Sciences, University of the Pacific, Arthur Dugoni School of Dentistry, San Francisco, USA.
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Sherchand SP, Ibana JA, Zea AH, Quayle AJ, Aiyar A. The High-Risk Human Papillomavirus E6 Oncogene Exacerbates the Negative Effect of Tryptophan Starvation on the Development of Chlamydia trachomatis. PLoS One 2016; 11:e0163174. [PMID: 27658027 PMCID: PMC5033384 DOI: 10.1371/journal.pone.0163174] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/02/2016] [Indexed: 12/26/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen that requires specific essential nutrients from the host cell, one of which is the amino acid tryptophan. In this context interferon gamma (IFNγ) is the major host protective cytokine against chlamydial infections because it induces the expression of the host enzyme, indoleamine 2,3-dioxygenase 1, that degrades tryptophan, thereby restricting bacterial replication. The mechanism by which IFNγ acts has been dissected in vitro using epithelial cell-lines such as HeLa, HEp-2, or the primary-like endocervical cell-line A2EN. All these cell-lines express the high-risk human papillomavirus oncogenes E6 & E7. While screening cell-lines to identify those suitable for C. trachomatis co-infections with other genital pathogens, we unexpectedly found that tryptophan starvation did not completely block chlamydial development in cell-lines that were HR-HPV negative, such as C33A and 293. Therefore, we tested the hypothesis that HR-HPV oncogenes modulate the effect of tryptophan starvation on chlamydial development by comparing chlamydial development in HeLa and C33A cell-lines that were both derived from cervical carcinomas. Our results indicate that during tryptophan depletion, unlike HeLa, C33A cells generate sufficient intracellular tryptophan via proteasomal activity to permit C. trachomatis replication. By generating stable derivatives of C33A that expressed HPV16 E6, E7 or E6 & E7, we found that E6 expression alone was sufficient to convert C33A cells to behave like HeLa during tryptophan starvation. The reduced tryptophan levels in HeLa cells have a biological consequence; akin to the previously described effect of IFNγ, tryptophan starvation protects C. trachomatis from clearance by doxycycline in HeLa but not C33A cells. Curiously, when compared to the known Homo sapiens proteome, the representation of tryptophan in the HR-HPV E6 & E6AP degradome is substantially lower, possibly providing a mechanism that underlies the lowered intracellular free tryptophan levels in E6-expressing cells during starvation.
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Affiliation(s)
- Shardulendra P. Sherchand
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana, 70112, United States of America
| | - Joyce A. Ibana
- Institute of Biology, University of the Philippines, Diliman, Quezon City, Philippines, PH, 1101
| | - Arnold H. Zea
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana, 70112, United States of America
| | - Alison J. Quayle
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana, 70112, United States of America
| | - Ashok Aiyar
- Department of Microbiology, Immunology & Parasitology, LSU Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana, 70112, United States of America
- * E-mail:
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Beyond Tryptophan Synthase: Identification of Genes That Contribute to Chlamydia trachomatis Survival during Gamma Interferon-Induced Persistence and Reactivation. Infect Immun 2016; 84:2791-801. [PMID: 27430273 DOI: 10.1128/iai.00356-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/15/2016] [Indexed: 12/31/2022] Open
Abstract
Chlamydia trachomatis can enter a viable but nonculturable state in vitro termed persistence. A common feature of C. trachomatis persistence models is that reticulate bodies fail to divide and make few infectious progeny until the persistence-inducing stressor is removed. One model of persistence that has relevance to human disease involves tryptophan limitation mediated by the host enzyme indoleamine 2,3-dioxygenase, which converts l-tryptophan to N-formylkynurenine. Genital C. trachomatis strains can counter tryptophan limitation because they encode a tryptophan-synthesizing enzyme. Tryptophan synthase is the only enzyme that has been confirmed to play a role in interferon gamma (IFN-γ)-induced persistence, although profound changes in chlamydial physiology and gene expression occur in the presence of persistence-inducing stressors. Thus, we screened a population of mutagenized C. trachomatis strains for mutants that failed to reactivate from IFN-γ-induced persistence. Six mutants were identified, and the mutations linked to the persistence phenotype in three of these were successfully mapped. One mutant had a missense mutation in tryptophan synthase; however, this mutant behaved differently from previously described synthase null mutants. Two hypothetical genes of unknown function, ctl0225 and ctl0694, were also identified and may be involved in amino acid transport and DNA damage repair, respectively. Our results indicate that C. trachomatis utilizes functionally diverse genes to mediate survival during and reactivation from persistence in HeLa cells.
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Abstract
Etiology, transmission and protection: Chlamydia
trachomatis is the leading cause of bacterial sexually transmitted
infection (STI) globally. However, C. trachomatis also causes
trachoma in endemic areas, mostly Africa and the Middle East, and is a leading
cause of preventable blindness worldwide. Epidemiology, incidence and
prevalence: The World Health Organization estimates 131 million
new cases of C. trachomatis genital infection occur annually.
Globally, infection is most prevalent in young women and men (14-25 years),
likely driven by asymptomatic infection, inadequate partner treatment and
delayed development of protective immunity.
Pathology/Symptomatology: C.
trachomatis infects susceptible squamocolumnar or transitional
epithelial cells, leading to cervicitis in women and urethritis in men. Symptoms
are often mild or absent but ascending infection in some women may lead to
Pelvic Inflammatory Disease (PID), resulting in reproductive sequelae such as
ectopic pregnancy, infertility and chronic pelvic pain. Complications of
infection in men include epididymitis and reactive arthritis.
Molecular mechanisms of infection: Chlamydiae
manipulate an array of host processes to support their obligate intracellular
developmental cycle. This leads to activation of signaling pathways resulting in
disproportionate influx of innate cells and the release of tissue damaging
proteins and pro-inflammatory cytokines. Treatment and
curability: Uncomplicated urogenital infection is treated with
azithromycin (1 g, single dose) or doxycycline (100 mg twice daily x 7 days).
However, antimicrobial treatment does not ameliorate established disease. Drug
resistance is rare but treatment failures have been described. Development of an
effective vaccine that protects against upper tract disease or that limits
transmission remains an important goal.
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Affiliation(s)
- Catherine M O'Connell
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Morgan E Ferone
- Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Radomski N, Einenkel R, Müller A, Knittler MR. Chlamydia-host cell interaction not only from a bird's eye view: some lessons fromChlamydia psittaci. FEBS Lett 2016; 590:3920-3940. [DOI: 10.1002/1873-3468.12295] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 07/06/2016] [Accepted: 07/07/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Nadine Radomski
- Friedrich-Loeffler-Institut; Institute of Immunology; Isle of Riems Germany
| | - Rebekka Einenkel
- Friedrich-Loeffler-Institut; Institute of Immunology; Isle of Riems Germany
| | - Anne Müller
- Friedrich-Loeffler-Institut; Institute of Immunology; Isle of Riems Germany
| | - Michael R Knittler
- Friedrich-Loeffler-Institut; Institute of Immunology; Isle of Riems Germany
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Chlamydia trachomatis Genital Tract Infections: When Host Immune Response and the Microbiome Collide. Trends Microbiol 2016; 24:750-765. [PMID: 27320172 DOI: 10.1016/j.tim.2016.05.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 05/06/2016] [Accepted: 05/25/2016] [Indexed: 02/08/2023]
Abstract
Genital infections with Chlamydia trachomatis continue to be a major health problem worldwide. While some individuals clear their infection (presumed to be the result of an effective Th1/interferon-γ response), others develop chronic infections and some are prone to repeat infections. In females in particular, chronic asymptomatic infections are common and can lead to pelvic inflammatory disease and infertility. Recent studies suggest that the genital tract microbiota could be a significant factor and explain person-to-person variation in C. trachomatis infections. One hypothesis suggests that C. trachomatis can use its trpBA genes to rescue tryptophan from indole, which is a product of anaerobic members of the genital tract microbiota. Women with particular microbiota types, such as seen in bacterial vaginosis, have increased numbers of anaerobes, and this would enable the chlamydia in these individuals to overcome the host's interferon-γ attempts to eliminate it, resulting in more repeat and/or chronic infections.
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Association of the in vitro susceptibility of clinical isolates of chlamydia trachomatis with serovar and duration of antibiotic exposure. Sex Transm Dis 2015; 42:115-9. [PMID: 25668641 DOI: 10.1097/olq.0000000000000241] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The presence of persistent Chlamydia trachomatis infection after treatment does not always correlate with in vitro susceptibility testing. METHODS The in vitro minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of azithromycin, clarithromycin, roxithromycin, doxycycline, tetracycline, ofloxacin, and penicillin were tested against 61 clinical isolates of C. trachomatis on 6 serovars, and the MIC/MBC of azithromycin and ofloxacin at different points in time after antibiotic administration to infected cultures. RESULTS Of the 7 antibiotics tested, clarithromycin showed the greatest activity against C. trachomatis isolates with MIC90 of 0.032 μg/mL and MBC90 of 0.064 μg/mL, followed by doxycycline with MIC90 0.064 μg/mL and MBC90 0.064 μg/mL, and azithromycin with MIC90 0.160 μg/mL and MBC90 0.320 μg/mL. Azithromycin had roughly the same MIC50 values (0.08 μg/mL) as the other serovars isolates tested, and other antibiotics showed a 2- to 4-fold difference in MICs50 between serovars. In addition, an increase in the azithromyin MIC was observed by 8 hours and the ofloxacin MIC by 16 hours. At 24 hours, the azithromycin MICs were greater than 40 μg/mL and ofloxacin MICs were greater than 64 μg/mL. CONCLUSIONS The current data demonstrated that the antimicrobial susceptibility of C. trachomatis was influenced by both the serovar type and the duration of exposure to antibiotics in infected cultures.
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Jiang N, Zhao G, Lin J, Hu L, Che C, Li C, Wang Q, Xu Q, Peng X. Indoleamine 2,3-Dioxygenase Is Involved in the Inflammation Response of Corneal Epithelial Cells to Aspergillus fumigatus Infections. PLoS One 2015; 10:e0137423. [PMID: 26361229 PMCID: PMC4567309 DOI: 10.1371/journal.pone.0137423] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 08/17/2015] [Indexed: 01/09/2023] Open
Abstract
Indoleamine 2,3-dioxygenase (IDO), which is mainly expressed in activated dendritic cells, is known as a regulator of immune responses. However, the role of IDO in immune responses against fungal corneal infection has not been investigated. To evaluate the regulatory mechanisms of IDO in fungal inflammation, we resorted to human corneal epithelial cells (HCECs), known as the first barrier of cornea against pathogenic microorganisms. We found that IDO was significantly up-regulated in corneal epithelium infected with Aspergillus fumigatus (A. fumigatus) and HCECs incubated with spores of A. fumigatus. Furthermore, IDO inhibitor (1-methyltryptophan, 1-MT) enhanced inflammatory cytokines IL-1β and IL-6 expression which were up-regulated by A. fumigatus spores infection. Dectin-1, as one of the important C-type lectin receptors, can identify β-glucan, and mediate fungal innate immune responses. In the present study, pre-treatment with curdlan, a Dectin-1 agonist, further enhanced IDO expression compared with A. fumigatus stimulation. While laminarin, the Dectin-1 specific inhibitor, partially inhibited IDO expression stimulated by A. fumigatus. Further studies demonstrated inhibition of IDO activity amplified the expressions of inflammatory cytokines IL-1β and IL-6 induced by activation of Dectin-1. These results suggested that IDO was involved in the immune responses of fungal keratitis. The activation of Dectin-1 may contribute to A. fumigatus spores-induced up-regulation of IDO.
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MESH Headings
- Animals
- Aspergillus fumigatus/genetics
- Cytokines/metabolism
- Disease Models, Animal
- Epithelium, Corneal/metabolism
- Epithelium, Corneal/microbiology
- Epithelium, Corneal/pathology
- Female
- Gene Expression
- Humans
- Indoleamine-Pyrrole 2,3,-Dioxygenase/antagonists & inhibitors
- Indoleamine-Pyrrole 2,3,-Dioxygenase/genetics
- Indoleamine-Pyrrole 2,3,-Dioxygenase/metabolism
- Inflammation Mediators/metabolism
- Keratitis/diagnosis
- Keratitis/metabolism
- Keratitis/microbiology
- Lectins, C-Type/metabolism
- Mice
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- beta-Glucans/pharmacology
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Affiliation(s)
- Nan Jiang
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China
| | - Guiqiu Zhao
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China
- * E-mail:
| | - Jing Lin
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China
| | - Liting Hu
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China
| | - Chengye Che
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China
| | - Cui Li
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China
| | - Qian Wang
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China
| | - Qiang Xu
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China
| | - Xudong Peng
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong Province, China
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40
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Dumoux M, Menny A, Delacour D, Hayward RD. A Chlamydia effector recruits CEP170 to reprogram host microtubule organization. J Cell Sci 2015. [PMID: 26220855 PMCID: PMC4582400 DOI: 10.1242/jcs.169318] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The obligate intracellular bacterial pathogen Chlamydia trachomatis deploys virulence effectors to subvert host cell functions enabling its replication within a specialized membrane-bound compartment termed an inclusion. The control of the host cytoskeleton is crucial for Chlamydia uptake, inclusion biogenesis and cell exit. Here, we demonstrate how a Chlamydia effector rearranges the microtubule (MT) network by initiating organization of the MTs at the inclusion surface. We identified an inclusion-localized effector that is sufficient to interfere with MT assembly, which we named inclusion protein acting on MTs (IPAM). We established that IPAM recruits and stimulates the centrosomal protein 170 kDa (CEP170) to hijack the MT organizing functions of the host cell. We show that CEP170 is essential for chlamydial control of host MT assembly, and is required for inclusion morphogenesis and bacterial infectivity. Together, we demonstrate how a pathogen effector reprograms the host MT network to support its intracellular development.
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Affiliation(s)
- Maud Dumoux
- Institute of Structural and Molecular Biology, Birkbeck and University College London, Malet Street, London WC1E 7HX, UK
| | - Anais Menny
- Institute of Structural and Molecular Biology, Birkbeck and University College London, Malet Street, London WC1E 7HX, UK
| | - Delphine Delacour
- Cell Adhesion and Mechanics Group, Institut Jacques Monod, CNRS UMR7592, Université Paris Diderot, 15 rue Helene Brion, Paris 75013, France
| | - Richard D Hayward
- Institute of Structural and Molecular Biology, Birkbeck and University College London, Malet Street, London WC1E 7HX, UK
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Abstract
IDO1 (indoleamine 2,3-dioxygenase 1) is a member of a unique class of mammalian haem dioxygenases that catalyse the oxidative catabolism of the least-abundant essential amino acid, L-Trp (L-tryptophan), along the kynurenine pathway. Significant increases in knowledge have been recently gained with respect to understanding the fundamental biochemistry of IDO1 including its catalytic reaction mechanism, the scope of enzyme reactions it catalyses, the biochemical mechanisms controlling IDO1 expression and enzyme activity, and the discovery of enzyme inhibitors. Major advances in understanding the roles of IDO1 in physiology and disease have also been realised. IDO1 is recognised as a prominent immune regulatory enzyme capable of modulating immune cell activation status and phenotype via several molecular mechanisms including enzyme-dependent deprivation of L-Trp and its conversion into the aryl hydrocarbon receptor ligand kynurenine and other bioactive kynurenine pathway metabolites, or non-enzymatic cell signalling actions involving tyrosine phosphorylation of IDO1. Through these different modes of biochemical signalling, IDO1 regulates certain physiological functions (e.g. pregnancy) and modulates the pathogenesis and severity of diverse conditions including chronic inflammation, infectious disease, allergic and autoimmune disorders, transplantation, neuropathology and cancer. In the present review, we detail the current understanding of IDO1’s catalytic actions and the biochemical mechanisms regulating IDO1 expression and activity. We also discuss the biological functions of IDO1 with a focus on the enzyme's immune-modulatory function, its medical implications in diverse pathological settings and its utility as a therapeutic target.
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Araújo EF, Loures FV, Bazan SB, Feriotti C, Pina A, Schanoski AS, Costa TA, Calich VLG. Indoleamine 2,3-dioxygenase controls fungal loads and immunity in Paracoccidioidomicosis but is more important to susceptible than resistant hosts. PLoS Negl Trop Dis 2014; 8:e3330. [PMID: 25411790 PMCID: PMC4238999 DOI: 10.1371/journal.pntd.0003330] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 10/08/2014] [Indexed: 11/29/2022] Open
Abstract
Background Paracoccidioidomycosis, a primary fungal infection restricted to Latin America, is acquired by inhalation of fungal particles. The immunoregulatory mechanisms that control the severe and mild forms of paracoccidioidomycosis are still unclear. Indoleamine 2,3-dioxygenase (IDO), an IFN-γ induced enzyme that catalyzes tryptophan metabolism, can control host-pathogen interaction by inhibiting pathogen growth, T cell immunity and tissue inflammation. Methodology/Principal Findings In this study, we investigated the role of IDO in pulmonary paracoccidioidomycosis of susceptible and resistant mice. IDO was blocked by 1-methyl-dl-tryptophan (1MT), and fungal infection studied in vitro and in vivo. Paracoccidioides brasiliensis infection was more severe in 1MT treated than untreated macrophages of resistant and susceptible mice, concurrently with decreased production of kynurenines and IDO mRNA. Similar results were observed in the pulmonary infection. Independent of the host genetic pattern, IDO inhibition reduced fungal clearance but enhanced T cell immunity. The early IDO inhibition resulted in increased differentiation of dendritic and Th17 cells, accompanied by reduced responses of Th1 and Treg cells. Despite these equivalent biological effects, only in susceptible mice the temporary IDO blockade caused sustained fungal growth, increased tissue pathology and mortality rates. In contrast, resistant mice were able to recover the transitory IDO blockade by the late control of fungal burdens without enhanced tissue pathology. Conclusions/Significance Our studies demonstrate for the first time that in pulmonary paracoccidioidomycosis, IDO is an important immunoregulatory enzyme that promotes fungal clearance and inhibits T cell immunity and inflammation, with prominent importance to susceptible hosts. In fact, only in the susceptible background IDO inhibition resulted in uncontrolled tissue pathology and mortality rates. Our findings open new perspectives to understand the immunopathology of paracoccidioidomycosis, and suggest that an insufficient IDO activity could be associated with the severe cases of human PCM characterized by inefficient fungal clearance and excessive inflammation. Immunoprotection to paracoccidiodomycosis, a systemic mycosis endemic in Latin America, is mediated by T cell immunity whereas immunosuppression characterizes the severe forms of the disease. Indoleamine 2,3-dioxygenase (IDO), an enzyme mainly induced by IFN-γ, catabolizes tryptophan along the kynurenines pathway. Tryptophan deficiency has been associated with reduced pathogen growth, while elevated levels of kynurenines with suppressed immune responses. In this study, the role of IDO in pulmonary paracoccidioidomycosis was investigated using resistant and susceptible mice. In both mouse strains, IDO blockade by 1-methyl tryptophan resulted in inefficient fungal clearance accompanied by enhanced T cell immunity. Despite these equivalent biological effects, only in susceptible mice IDO inhibition caused progressive fungal growth and tissue pathology resulting in increased mortality. Our findings demonstrate for the first time that IDO exert a yet unexplored immunoregulatory role in pulmonary paracoccidioidomycosis that can be particularly important in the severe cases of the disease.
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Affiliation(s)
- Eliseu F. Araújo
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Flávio V. Loures
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Silvia B. Bazan
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Claudia Feriotti
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Adriana Pina
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Alessandra S. Schanoski
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Tânia A. Costa
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Vera L. G. Calich
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
- * E-mail:
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43
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Redgrove KA, McLaughlin EA. The Role of the Immune Response in Chlamydia trachomatis Infection of the Male Genital Tract: A Double-Edged Sword. Front Immunol 2014; 5:534. [PMID: 25386180 PMCID: PMC4209867 DOI: 10.3389/fimmu.2014.00534] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/09/2014] [Indexed: 01/16/2023] Open
Abstract
Chlamydia trachomatis (CT) is the most prevalent bacterial sexually transmitted infection in the world, with more than 100 million cases reported annually. While there have been extensive studies into the adverse effects that CT infection has on the female genital tract, and on the subsequent ability of these women to conceive, studies into the consequences on male fertility have been limited and controversial. This is in part due to the asymptomatic nature of the infection, where it is estimated that 50% of men with Chlamydia fail to show any symptoms. It is accepted, however, that acute and/or persistent CT infection is the causative agent for conditions such as urethritis, epididymitis, epididymo-orchitis, and potentially prostatitis. As with most infections, the immune system plays a fundamental role in the body’s attempts to eradicate the infection. The first and most important immune response to Chlamydia infection is a local one, whereby immune cells such as leukocytes are recruited to the site of infections, and subsequently secrete pro-inflammatory cytokines and chemokines such as interferon gamma. Immune cells also work to initiate and potentiate chronic inflammation through the production of reactive oxygen species (ROS), and the release of molecules with degradative properties including defensins, elastase, collagenase, cathespins, and lysozyme. This long-term inflammation can lead to cell proliferation (a possible precursor to cancer), tissue remodeling, and scarring, as well as being linked to the onset of autoimmune responses in genetically disposed individuals. This review will focus on the ability of the immune system to recognize and clear acute and persistent chlamydial infections in the male genital tract, and on the paradoxical damage that chronic inflammation resulting from the infection can cause on the reproductive health of the individual.
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Affiliation(s)
- Kate A Redgrove
- Priority Research Centre in Reproductive Biology and Chemical Biology, University of Newcastle , Callaghan, NSW , Australia ; School of Environmental and Life Science, University of Newcastle , Callaghan, NSW , Australia
| | - Eileen A McLaughlin
- Priority Research Centre in Reproductive Biology and Chemical Biology, University of Newcastle , Callaghan, NSW , Australia ; School of Environmental and Life Science, University of Newcastle , Callaghan, NSW , Australia
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44
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Schmidt SV, Schultze JL. New Insights into IDO Biology in Bacterial and Viral Infections. Front Immunol 2014; 5:384. [PMID: 25157255 PMCID: PMC4128074 DOI: 10.3389/fimmu.2014.00384] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/28/2014] [Indexed: 12/24/2022] Open
Abstract
Initially, indoleamine-2,3-dioxygenase (IDO) has been introduced as a bactericidal effector mechanism and has been linked to T-cell immunosuppression and tolerance. In recent years, evidence has been accumulated that IDO also plays an important role during viral infections including HIV, influenza, and hepatitis B and C. Moreover, novel aspects about the role of IDO in bacterial infections and sepsis have been revealed. Here, we review these recent findings highlighting the central role of IDO and tryptophan metabolism in many major human infections. Moreover, we also shed light on issues concerning human-specific and mouse-specific host–pathogen interactions that need to be considered when studying the biology of IDO in the context of infections.
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Affiliation(s)
- Susanne V Schmidt
- Genomics and Immunoregulation, LIMES-Institute, University of Bonn , Bonn , Germany
| | - Joachim L Schultze
- Genomics and Immunoregulation, LIMES-Institute, University of Bonn , Bonn , Germany
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45
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Chen J, Shao J, Cai R, Shen Y, Zhang R, Liu L, Qi T, Lu H. Anti-retroviral therapy decreases but does not normalize indoleamine 2,3-dioxygenase activity in HIV-infected patients. PLoS One 2014; 9:e100446. [PMID: 24983463 PMCID: PMC4077698 DOI: 10.1371/journal.pone.0100446] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 05/22/2014] [Indexed: 01/23/2023] Open
Abstract
Background Indoleamine 2,3-dioxygenase (IDO), which is mainly expressed in activated dendritic cells, catabolizes tryptophan to kynurenine and other downstream catabolites. It is known to be an immune mediator in HIV pathogenesis. The impact of anti-retroviral therapy on its activity has not been well established. Methods We measured systemic IDO activity (the ratio of plasma kynurenine to tryptophan) in HIV-infected patients before and after highly active antiretroviral therapy (HAART) and its association with a microbial translocation marker, soluble CD14 (sCD14). Results Among 76 participants, higher baseline IDO activity was associated with lower CD4+ T cell counts (P<0.05) and higher plasma sCD14 levels (P<0.001). After 1 year of HAART, IDO activity decreased significantly (P<0.01), but was still higher than in healthy controls (P<0.05). The baseline IDO activity did not predict CD4+ T cell recovery after 1 year of therapy. The percentages of myeloid and plasmacytoid dendritic cells were not correlated with IDO activity. Conclusions IDO activity is elevated in HIV-infected patients, which is partially associated with microbial translocation. HAART reduced, but did not normalize the activity of IDO.
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Affiliation(s)
- Jun Chen
- Department of Infectious Diseases, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Jiasheng Shao
- Department of Infectious Diseases, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Rentian Cai
- Department of Infectious Diseases, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Yinzhong Shen
- Department of Infectious Diseases, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Renfang Zhang
- Department of Infectious Diseases, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Li Liu
- Department of Infectious Diseases, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Tangkai Qi
- Department of Infectious Diseases, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Hongzhou Lu
- Department of Infectious Diseases, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
- Department of Infectious Diseases, HuaShan Hospital, Fudan University, Shanghai, China
- Department of Internal Medicine, Shanghai Medical College, Fudan University, Shanghai, China
- * E-mail:
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46
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Bachmann NL, Polkinghorne A, Timms P. Chlamydia genomics: providing novel insights into chlamydial biology. Trends Microbiol 2014; 22:464-72. [PMID: 24882432 DOI: 10.1016/j.tim.2014.04.013] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/18/2014] [Accepted: 04/28/2014] [Indexed: 12/12/2022]
Abstract
Chlamydiaceae are obligate intracellular pathogens that have successfully evolved to colonize a diverse range of hosts. There are currently 11 described species of Chlamydia, most of which have a significant impact on the health of humans or animals. Expanding chlamydial genome sequence information has revolutionized our understanding of chlamydial biology, including aspects of their unique lifecycle, host-pathogen interactions, and genetic differences between Chlamydia strains associated with different host and tissue tropisms. This review summarizes the major highlights of chlamydial genomics and reflects on the considerable impact these have had on understanding the biology of chlamydial pathogens and the changing nature of genomics tools in the 'post-genomics' era.
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Affiliation(s)
- Nathan L Bachmann
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4558, Australia
| | - Adam Polkinghorne
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4558, Australia
| | - Peter Timms
- Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4558, Australia.
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47
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Vickers DM, Osgood ND. The arrested immunity hypothesis in an immunoepidemiological model of Chlamydia transmission. Theor Popul Biol 2014; 93:52-62. [PMID: 24513099 DOI: 10.1016/j.tpb.2014.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 01/29/2014] [Accepted: 01/30/2014] [Indexed: 01/07/2023]
Abstract
For curable infectious diseases, public health strategies such as treatment can effectively shorten an individual's infectious period, and thus limit their role in transmission. However, because treatment effectively eliminates antigen impingement, these types of control strategies may also paradoxically impair the development of adaptive immune responses. For sexually transmitted Chlamydia trachomatis infections, this latter effect has been coined the arrested immunity hypothesis, and is discussed to carry significant epidemiological implications for those individuals who return to similar sexual networks with similar sexual behavior. Here, we examine the effect of antibiotic treatment on the spread of Chlamydia infection through a simple immunoepidemiological framework that characterizes the population as a collection of dynamically evolving individuals in small, paradigmatic networks. Within each individual there is an explicit representation of pathogen replication, accumulation and persistence of an immune response, followed by a gradual waning of that response once the infection is cleared. Individuals are then nested in networks, allowing the variability in the life history of their infection to be functions of both individual immune dynamics as well as their position in the network. Model results suggest that the timing and coverage of treatment are important contributors to the development of immunity and reinfection. In particular, the impact of treatment on the spread of infection between individuals can be beneficial, have no effect, or be deleterious depending on who is treated and when. Although we use sexually transmitted Chlamydia infection as an example, the observed results arise endogenously from a basic model structure, and thus warrant consideration to understanding the interaction of infection, treatment, and spread of other infectious diseases.
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Affiliation(s)
- David M Vickers
- Infection, Prevention, and Control, Alberta Health Services, Calgary, AB, Canada; Computational Epidemiology and Public Health Informatics Laboratory, University of Saskatchewan, Saskatoon, SK, Canada.
| | - Nathaniel D Osgood
- Computational Epidemiology and Public Health Informatics Laboratory, University of Saskatchewan, Saskatoon, SK, Canada; Department of Computer Science, University of Saskatchewan, Saskatoon, SK, Canada; School of Public Health, University of Saskatchewan, Saskatoon, SK, Canada
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48
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Leonhardt RM, Abrahimi P, Mitchell SM, Cresswell P. Three tapasin docking sites in TAP cooperate to facilitate transporter stabilization and heterodimerization. THE JOURNAL OF IMMUNOLOGY 2014; 192:2480-94. [PMID: 24501197 DOI: 10.4049/jimmunol.1302637] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The TAP translocates peptide Ags into the lumen of the endoplasmic reticulum for loading onto MHC class I molecules. MHC class I acquires its peptide cargo in the peptide loading complex, an oligomeric complex that the chaperone tapasin organizes by bridging TAP to MHC class I and recruiting accessory molecules such as ERp57 and calreticulin. Three tapasin binding sites on TAP have been described, two of which are located in the N-terminal domains of TAP1 and TAP2. The third binding site is present in the core transmembrane (TM) domain of TAP1 and is used only by the unassembled subunits. Tapasin is required to promote TAP stability, but through which binding site(s) it is acting is unknown. In particular, the role of tapasin binding to the core TM domain of TAP1 single chains is mysterious because this interaction is lost upon TAP2 association. In this study, we map the respective binding site in TAP1 to the polar face of the amphipathic TM helix TM9 and identify key residues that are essential to establish the interaction. We find that this interaction is dispensable for the peptide transport function but essential to achieve full stability of human TAP1. The interaction is also required for proper heterodimerization of the transporter. Based on similar results obtained using TAP mutants that lack tapasin binding to either N-terminal domain, we conclude that all three tapasin-binding sites in TAP cooperate to achieve high transporter stability and efficient heterodimerization.
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49
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Abdelsamed H, Peters J, Byrne GI. Genetic variation in Chlamydia trachomatis and their hosts: impact on disease severity and tissue tropism. Future Microbiol 2013; 8:1129-1146. [PMID: 24020741 PMCID: PMC4009991 DOI: 10.2217/fmb.13.80] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Chlamydia trachomatis infections are a global health problem. This obligate intracellular bacterial pathogen comprises lymphogranuloma venereum (L1-L3), ocular (A-C) and genital (D-K) serovars. Although genetically similar, each serovar group differs in disease severity and tissue tropism through mechanisms that are not well understood. It is clear that host genetic differences also play a role in chlamydial disease outcome and key host polymorphisms are beginning to emerge from both human and experimental animal studies. In this review, we will highlight pathogen and host genes that link genetic diversity, disease severity and tissue tropism. We will also use this information to provide new insights that may be helpful in developing improved management strategies for these important pathogens.
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Affiliation(s)
- Hossam Abdelsamed
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Jan Peters
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Regional Biocontainment Laboratory, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Gerald I Byrne
- Department of Microbiology, Immunology & Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN, USA
- Regional Biocontainment Laboratory, University of Tennessee Health Sciences Center, Memphis, TN, USA
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50
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Niño-Castro A, Abdullah Z, Popov A, Thabet Y, Beyer M, Knolle P, Domann E, Chakraborty T, Schmidt SV, Schultze JL. The IDO1-induced kynurenines play a major role in the antimicrobial effect of human myeloid cells against Listeria monocytogenes. Innate Immun 2013; 20:401-11. [PMID: 23940074 DOI: 10.1177/1753425913496442] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Induction of indoleamine 2,3-dioxygenase (IDO1) is an established cellular response to infection with numerous pathogens. Several mechanisms, such as IDO1-mediated tryptophan (Trp) depletion, but also accumulation of Trp catabolites, have been associated with the antimicrobial effects of IDO(+) cells. Recent findings of IDO1 as an immunoinhibitory and signaling molecule extended these previous observations. Using infection of professional phagocytes with Listeria monocytogenes (L.m.) as a model, we illustrate that IDO1 induction is a species-specific event observed in human, but not murine myeloid, cells. Knockdown and inhibition experiments indicate that IDO1 enzymatic activity is required for the anti-L.m. effect. Surprisingly, the IDO1-mediated antimicrobial effect is less prominent when Trp is depleted, but can be significantly amplified by tryptophan excess, leading to increased accumulation of catabolites that promote enhanced bactericidal activity. We observed a pathogen-specific pattern with kynurenine and 3-hydroxy-kynurenine being most potent against L.m., but not against other bacteria. Hence, apparent discrepant findings concerning IDO1-mediated antimicrobial mechanisms can be reconciled by a model of species and pathogen-specificity of IDO1 function. Our findings highlight the necessity to consider species- and pathogen-specific aspects of host-pathogen interactions when elucidating the individual role of antimicrobial proteins such as IDO1.
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Affiliation(s)
- Andrea Niño-Castro
- 1Genomics and Immunoregulation, LIMES-Institute, University of Bonn, Bonn, Germany
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