1
|
Luo Y, Sun Z, Chen Q, Xiao J, Yan X, Li Y, Wu Y. TLR2 mediates autophagy through ERK signaling pathway in Chlamydia psittaci CPSIT_p7 protein-stimulated RAW264.7 cells. Microbiol Immunol 2023; 67:469-479. [PMID: 37615441 DOI: 10.1111/1348-0421.13096] [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: 04/21/2023] [Revised: 07/26/2023] [Accepted: 08/09/2023] [Indexed: 08/25/2023]
Abstract
Chlamydia psittaci is a zoonotic pathogen found in birds and humans. Macrophages, major components of the innate immune system, can resist chlamydial infections and trigger adaptive immune responses. However, the molecular mechanisms underlying the action of macrophages against C. psittaci infection are not well understood. This study investigated the roles and mechanisms of plasmid-encoded protein CPSIT_p7 of C. psittaci in regulating autophagy in RAW264.7 cells. The results demonstrated that stimulation of RAW264.7 with C. psittaci plasmid protein CPSIT_p7 induced the expressions of the autophagy signaling primary regulators LC3 and Beclin1, which could also significantly induce the phosphorylation levels of ERK, JNK, p38, and Akt. Next, siRNA knockdown of TLR2 resulted in significant downregulation of CPSIT_p7-triggered autophagy in RAW264.7 cells. Moreover, the extracellular regulated protein kinase (ERK) inhibitor PD98059 markedly reduced autophagy in CPSIT_p7-stimulated macrophages. In summary, these results indicated that TLR2 plays an essential role in the induction of autophagy through the ERK signaling pathway in CPSIT_p7-stimulated RAW264.7 cells.
Collapse
Affiliation(s)
- Ying Luo
- Institution of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China
- Department of Molecular Diagnosis Center, The Sixth Affiliated Hospital of Guangzhou Medical University/Qingyuan People's Hospital, Qingyuan, China
| | - Zhenjie Sun
- Institution of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China
| | - Qian Chen
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Jian Xiao
- Institution of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China
- Department of Clinical Laboratory, Nanhua Affiliated Hospital, University of South China, Hengyang, China
| | - XiaoLiang Yan
- Institution of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China
| | - Yumeng Li
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Yimou Wu
- Institution of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China
| |
Collapse
|
2
|
Suzuki M, Funakoshi T, Kumagai K, Komatsu M, Waguri S. ATG9A supports Chlamydia trachomatis infection via autophagy-independent mechanisms. Microbiol Spectr 2023; 11:e0277423. [PMID: 37707289 PMCID: PMC10580829 DOI: 10.1128/spectrum.02774-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 07/18/2023] [Indexed: 09/15/2023] Open
Abstract
Chlamydia trachomatis infection can be regulated by autophagy-related (ATG) genes. Here, we found that the depletion of ATG9A, one of the core ATG genes, in HeLa cells suppressed C. trachomatis growth in the inclusion. The growth was restored by re-expressing ATG9A or an ATG9A mutant impairing lipid scramblase activity in ATG9A-knockout (KO) cells. Moreover, the depletion of lipid transfer proteins ATG2A/B, responsible for isolation membrane expansion together with ATG9A, did not significantly alter the growth, suggesting that the non-autophagic function of ATG9A supports C. trachomatis infection. ATG9A-KO cells showed no infection-induced redistribution of the Golgi from the perinuclear region to inclusion, which was restored by re-expressing the mutant but not the ATG9A mutant lacking an N-terminal adapter protein-binding domain. Re-expression of the N-terminal deletion mutant in ATG9A-KO cells did not rescue C. trachomatis growth, suggesting the importance of this domain for its growth. Although ATG9A-KO cells showed enhanced TBK1 activation, interferon (IFN)-β was not significantly increased, excluding the possibility that upregulation of stimulator of IFN genes (STING) signaling suppressed bacterial growth. Taken together, these findings suggest that the proper trafficking, rather than the isolation membrane expansion function, of ATG9A assists C. trachomatis growth in the inclusion. IMPORTANCE ATG9A is an autophagy-related gene that functions during the isolation membrane expansion process to form autophagosomes, but it also has other functions independent of autophagy. In this study, we employed ATG9A-deficient HeLa cells and found that the absence of ATG9A negatively impacted proliferation of Chlamydia trachomatis in inclusions. Furthermore, rescue experiments using ATG9A mutants revealed that this action was mediated not by its autophagic function but by its binding ability to clathrin adapter proteins. These findings suggest that the proper trafficking of ATG9A assists C. trachomatis growth in the inclusion.
Collapse
Affiliation(s)
- Michitaka Suzuki
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine, Hikarigaoka, Fukushima, Japan
| | - Tomoko Funakoshi
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Keigo Kumagai
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, Japan
| | - Masaaki Komatsu
- Department of Physiology, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Satoshi Waguri
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine, Hikarigaoka, Fukushima, Japan
| |
Collapse
|
3
|
Clemente TM, Angara RK, Gilk SD. Establishing the intracellular niche of obligate intracellular vacuolar pathogens. Front Cell Infect Microbiol 2023; 13:1206037. [PMID: 37645379 PMCID: PMC10461009 DOI: 10.3389/fcimb.2023.1206037] [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: 04/14/2023] [Accepted: 07/21/2023] [Indexed: 08/31/2023] Open
Abstract
Obligate intracellular pathogens occupy one of two niches - free in the host cell cytoplasm or confined in a membrane-bound vacuole. Pathogens occupying membrane-bound vacuoles are sequestered from the innate immune system and have an extra layer of protection from antimicrobial drugs. However, this lifestyle presents several challenges. First, the bacteria must obtain membrane or membrane components to support vacuole expansion and provide space for the increasing bacteria numbers during the log phase of replication. Second, the vacuole microenvironment must be suitable for the unique metabolic needs of the pathogen. Third, as most obligate intracellular bacterial pathogens have undergone genomic reduction and are not capable of full metabolic independence, the bacteria must have mechanisms to obtain essential nutrients and resources from the host cell. Finally, because they are separated from the host cell by the vacuole membrane, the bacteria must possess mechanisms to manipulate the host cell, typically through a specialized secretion system which crosses the vacuole membrane. While there are common themes, each bacterial pathogen utilizes unique approach to establishing and maintaining their intracellular niches. In this review, we focus on the vacuole-bound intracellular niches of Anaplasma phagocytophilum, Ehrlichia chaffeensis, Chlamydia trachomatis, and Coxiella burnetii.
Collapse
Affiliation(s)
| | | | - Stacey D. Gilk
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| |
Collapse
|
4
|
Komijani E, Parhizkar F, Abdolmohammadi-Vahid S, Ahmadi H, Nouri N, Yousefi M, Aghebati-Maleki L. Autophagy-mediated immune system regulation in reproductive system and pregnancy-associated complications. J Reprod Immunol 2023; 158:103973. [PMID: 37295066 DOI: 10.1016/j.jri.2023.103973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/29/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023]
Abstract
Autophagy lysosomal degradation is the main cell mechanism in cellular, tissue and organismal homeostasis and is controlled by autophagy-related genes (ATG). Autophagy has important effects in cellular physiology, including adaptation to metabolic stress, removal of dangerous cargo (such as protein aggregates, damaged organelles, and intracellular pathogens), regeneration during differentiation and development, and prevention of genomic damage in general. Also, it has been found that autophagy is essential for pre-implantation, development, and maintaining embryo survival in mammals. Under certain conditions, autophagy may be detrimental through pro-survival effects such as cancer progression or through possible cell death-promoting effects. Hormonal changes and environmental stress can initiate autophagy in reproductive physiology. The activity of autophagy can be upregulated under conditions like a lack of nutrients, inflammation, hypoxia, and infections. In this regard the dysregulation of autophagy involved in some pregnancy complications such as preeclampsia (PE) and pregnancy loss, and has a major impact on reproductive outcomes. Therefore, we aimed to discuss the relationship between autophagy and the female reproductive system, with a special focus on the immune system, and its role in fetal and maternal health.
Collapse
Affiliation(s)
- Erfan Komijani
- Department of Veterinary Medicine, Tabriz Branch, Islamic Azad University, Tabriz, Iran
| | - Forough Parhizkar
- Student's Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Hamid Ahmadi
- Department of Medical Biology and Central Electron Microscope Laboratory, Medical School, Pécs University, Pécs, Hungary
| | - Narjes Nouri
- Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mehdi Yousefi
- Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | | |
Collapse
|
5
|
Chlamydia trachomatis induces autophagy by p62 in HeLa cell. World J Microbiol Biotechnol 2021; 37:50. [PMID: 33590353 DOI: 10.1007/s11274-021-03014-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 01/28/2021] [Indexed: 10/22/2022]
Abstract
Chlamydia trachomatis is the most common bacterial pathogen causing sexually transmitted diseases. C. trachomatis infection is closely related to the development of cervical cancer, studies have shown that C. trachomatis can induce host cell autophagy. The autophagy related gene p62 plays an important role in the process of autophagy. To further understand the role of autophagy-associated gene p62 in autophagy of HeLa cells induced by C. trachomatis, p62-silencing cell line, HeLa229-shp62, and control cell line, HeLa229-shNC, were constructed, and a C. trachomatis-infected cell model was established. The autophagosome and C. trachomatis inclusions were observed under electron microscope. The autophagy level of C. trachomatis-infected HeLa cells was detected by Western blot. The results suggested that knockdown of p62 affected neither C. trachomatis infection of HeLa cells nor the initiation of C. trachomatis-induced autophagy, but at 48 h post C. trachomatis infection, autophagy levels were significantly inhibited in p62 silencing host cells. The study demonstrated the important role of p62 in the autophagy induced by C. trachomatis in HeLa cells, which could provide data support and theoretical basis for exploring the pathogenesis and prevention of C. trachomatis.
Collapse
|
6
|
Wang F, Zhang L, Lu X, Zhu Q, Shi T, Lu R, Yu P, Zhang H, Wang Y. Inflammatory mechanism of Chlamydia trachomatis-infected HeLa229 cells regulated by Atg5. Biochem Biophys Res Commun 2019; 520:205-210. [PMID: 31585730 DOI: 10.1016/j.bbrc.2019.09.132] [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: 08/31/2019] [Accepted: 09/28/2019] [Indexed: 10/25/2022]
Abstract
The relation between autophagy and Chlamydia trachomatis infection remain inconclusive. In order to further understand the role of autophagy in C. trachomatis-infected cells. Atg5 silenced HeLa229 cell line was used to establish an autophagy inhibition C. trachomatis infection model. The results suggested that Atg5 served a key regulatory role in the autophagy of C. trachomatis-infected cells. Silencing Atg5 significantly inhibited the autophagy level of the infected cells. Furthermore, Atg5 knockdown led to increased secretion of proinflammatory cytokines IL-1β, IL-6, IFN-γ and TNF-α, and decreased secretion of anti-inflammatory cytokine IL-10 in C. trachomatis-infected cells after autophagy induction, which suggested the anti-inflammatory role of autophagy during chlamydia infection. This study reveals some physiological and pathological roles of autophagy during C. trachomatis infection, which would provide clues in the treatment of chronic chlamydia infection.
Collapse
Affiliation(s)
- Fuyan Wang
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Lei Zhang
- Department of Urinary Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiaofang Lu
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Quan Zhu
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Tingting Shi
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Rong Lu
- Department of Obstetrics and Gynecology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ping Yu
- Department of Immunology, School of Basic Medical Science, Central South University, Changsha, Hunan, China
| | - Hongbo Zhang
- Department of Pathology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China.
| | - Yong Wang
- Department of Forensic Science, School of Basic Medical Science, Central South University, Changsha, Hunan, China.
| |
Collapse
|
7
|
Lausen M, Christiansen G, Bouet Guldbæk Poulsen T, Birkelund S. Immunobiology of monocytes and macrophages during Chlamydia trachomatis infection. Microbes Infect 2018; 21:73-84. [PMID: 30528899 DOI: 10.1016/j.micinf.2018.10.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/11/2018] [Accepted: 10/11/2018] [Indexed: 02/03/2023]
Abstract
Infections caused by the intracellular bacterium Chlamydia trachomatis are a global health burden affecting more than 100 million people annually causing damaging long-lasting infections. In this review, we will present and discuss important aspects of the interaction between C. trachomatis and monocytes/macrophages.
Collapse
Affiliation(s)
- Mads Lausen
- Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 3b, 9220 Aalborg Ø, Denmark.
| | - Gunna Christiansen
- Department of Biomedicine, Aarhus University, Wilhelms Meyers Allé 4, 8000 Aarhus, Denmark
| | | | - Svend Birkelund
- Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 3b, 9220 Aalborg Ø, Denmark
| |
Collapse
|
8
|
Fischer A, Rudel T. Safe haven under constant attack-The Chlamydia-containing vacuole. Cell Microbiol 2018; 20:e12940. [PMID: 30101516 DOI: 10.1111/cmi.12940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 07/24/2018] [Accepted: 07/31/2018] [Indexed: 11/30/2022]
Abstract
Chlamydia belong to the group of obligate intracellular bacteria that reside in a membrane bound vacuole during the entire intracellular phase of their life cycle. This vacuole called inclusion shields the bacteria from adverse influences in the cytosol of the host cell like the destructive machinery of the cell-autonomous defence system. The inclusion thereby prevents the digestion and eradication in specialised compartments of the intact and viable cell called phagolysosomes or autophagolysosomes. It is becoming more and more evident that keeping the inclusion intact also prevents the onset of cell intrinsic cell death programmes that are activated upon damage of the inclusion and direct the cell to destruct itself and the pathogen inside. Chlamydia secrete numerous proteins into the inclusion membrane to protect and stabilise their unique niche inside the host cell. We will focus in this review on the diverse attack strategies of the host aiming at the destruction of the Chlamydia-containing inclusion and will summarise the current knowledge on the protection mechanisms elaborated by the bacteria to maintain the integrity of their replication niche.
Collapse
Affiliation(s)
- Annette Fischer
- Department of Microbiology, University of Würzburg Biocenter, Würzburg, Germany
| | - Thomas Rudel
- Department of Microbiology, University of Würzburg Biocenter, Würzburg, Germany
| |
Collapse
|
9
|
Lei W, Li Q, Su S, Bu J, Huang Q, Li Z. Chlamydia trachomatis plasmid-encoded protein pORF5 protects mitochondrial function by inducing mitophagy and increasing HMGB1 expression. Pathog Dis 2017; 75:4443198. [PMID: 29040500 DOI: 10.1093/femspd/ftx111] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 10/10/2017] [Indexed: 12/22/2022] Open
Affiliation(s)
- Wenbo Lei
- Institute of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, No. 28, Changsheng West Road Hengyang, Hunan 421001, P.R. China
| | - Qun Li
- Institute of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, No. 28, Changsheng West Road Hengyang, Hunan 421001, P.R. China
| | - Shengmei Su
- Institute of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, No. 28, Changsheng West Road Hengyang, Hunan 421001, P.R. China
| | - Jichang Bu
- Institute of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, No. 28, Changsheng West Road Hengyang, Hunan 421001, P.R. China
| | - Qiulin Huang
- Department of General Surgery, the First Affiliated Hospital of University of South China, No. 69, Chuanshan Road, Hengyang, Hunan 421001, P.R. China
| | - Zhongyu Li
- Institute of Pathogenic Biology, Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, No. 28, Changsheng West Road Hengyang, Hunan 421001, P.R. China
| |
Collapse
|
10
|
Chlamydia trachomatis: the Persistent Pathogen. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00203-17. [PMID: 28835360 DOI: 10.1128/cvi.00203-17] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium whose only natural host is humans. Although presenting as asymptomatic in most women, genital tract chlamydial infections are a leading cause of pelvic inflammatory disease, tubal factor infertility, and ectopic pregnancy. C. trachomatis has evolved successful mechanisms to avoid destruction by autophagy and the host immune system and persist within host epithelial cells. The intracellular form of this organism, the reticulate body, can enter into a persistent nonreplicative but viable state under unfavorable conditions. The infectious form of the organism, the elementary body, is again generated when the immune attack subsides. In its persistent form, C. trachomatis ceases to produce its major structural and membrane components, but synthesis of its 60-kDa heat shock protein (hsp60) is greatly upregulated and released from the cell. The immune response to hsp60, perhaps exacerbated by repeated cycles of productive infection and persistence, may promote damage to fallopian tube epithelial cells, scar formation, and tubal occlusion. The chlamydial and human hsp60 proteins are very similar, and hsp60 is one of the first proteins produced by newly formed embryos. Thus, the development of immunity to epitopes in the chlamydial hsp60 that are also present in the corresponding human hsp60 may increase susceptibility to pregnancy failure in infected women. Delineation of host factors that increase the likelihood that C. trachomatis will avoid immune destruction and survive within host epithelial cells and utilization of this knowledge to design individualized preventative and treatment protocols are needed to more effectively combat infections by this persistent pathogen.
Collapse
|
11
|
Chlamydia muridarum Infection of Macrophages Stimulates IL-1 β Secretion and Cell Death via Activation of Caspase-1 in an RIP3-Independent Manner. BIOMED RESEARCH INTERNATIONAL 2017; 2017:1592365. [PMID: 28660207 PMCID: PMC5474261 DOI: 10.1155/2017/1592365] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 05/09/2017] [Indexed: 11/18/2022]
Abstract
Chlamydiae are Gram-negative bacteria, which replicate exclusively in the infected host cells. Infection of the host cells by Chlamydiae stimulates the innate immune system leading to an inflammatory response, which is manifested not only by secretion of proinflammatory cytokines such as IL-1β from monocytes, macrophages, and dendritic cells, but also possibly by cell death mediated by Caspase-1 pyroptosis. RIP3 is a molecular switch that determines the development of necrosis or inflammation. However, the involvement of RIP3 in inflammasome activation by Chlamydia muridarum infection has not been clarified. Here, we assessed the role of RIP3 in synergy with Caspase-1 in the induction of IL-1β production in BMDM after either LPS/ATP or Chlamydia muridarum stimulation. The possibility of pyroptosis and necroptosis interplays and the role of RIP3 in IL-1β production during Chlamydia muridarum infection in BMDM was investigated as well. The data indicated that RIP3 is involved in NLRP3 inflammasome activation in LPS/ATP-stimulated BMDMs but not in Chlamydia muridarum infection. Pyroptosis occurred in BMDM after LPS/ATP stimulation or Chlamydia muridarum infection. Moreover, the results also illuminated the important role of the Caspase-1-mediated pyroptosis process which does not involve RIP3. Taken together, these observations may help shed new light on details in inflammatory signaling pathways activated by Chlamydia muridarum infection.
Collapse
|
12
|
Fischer A, Rudel T. Subversion of Cell-Autonomous Host Defense by Chlamydia Infection. Curr Top Microbiol Immunol 2016; 412:81-106. [PMID: 27169422 DOI: 10.1007/82_2016_13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Obligate intracellular bacteria entirely depend on the metabolites of their host cell for survival and generation of progeny. Due to their lifestyle inside a eukaryotic cell and the lack of any extracellular niche, they have to perfectly adapt to compartmentalized intracellular environment of the host cell and counteract the numerous defense strategies intrinsically present in all eukaryotic cells. This so-called cell-autonomous defense is present in all cell types encountering Chlamydia infection and is in addition closely linked to the cellular innate immune defense of the mammalian host. Cell type and chlamydial species-restricted mechanisms point a long-term evolutionary adaptation that builds the basis of the currently observed host and cell-type tropism among different Chlamydia species. This review will summarize the current knowledge on the strategies pathogenic Chlamydia species have developed to subvert and overcome the multiple mechanisms by which eukaryotic cells defend themselves against intracellular pathogens.
Collapse
Affiliation(s)
- Annette Fischer
- Department of Microbiology and Biocenter, University of Würzburg, Am Hubland, 97074, Wuerzburg, Germany
| | - Thomas Rudel
- Department of Microbiology and Biocenter, University of Würzburg, Am Hubland, 97074, Wuerzburg, Germany.
| |
Collapse
|
13
|
Steele S, Brunton J, Kawula T. The role of autophagy in intracellular pathogen nutrient acquisition. Front Cell Infect Microbiol 2015; 5:51. [PMID: 26106587 PMCID: PMC4460576 DOI: 10.3389/fcimb.2015.00051] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 05/26/2015] [Indexed: 01/01/2023] Open
Abstract
Following entry into host cells intracellular pathogens must simultaneously evade innate host defense mechanisms and acquire energy and anabolic substrates from the nutrient-limited intracellular environment. Most of the potential intracellular nutrient sources are stored within complex macromolecules that are not immediately accessible by intracellular pathogens. To obtain nutrients for proliferation, intracellular pathogens must compete with the host cell for newly-imported simple nutrients or degrade host nutrient storage structures into their constituent components (fatty acids, carbohydrates, and amino acids). It is becoming increasingly evident that intracellular pathogens have evolved a wide variety of strategies to accomplish this task. One recurrent microbial strategy is to exploit host degradative processes that break down host macromolecules into simple nutrients that the microbe can use. Herein we focus on how a subset of bacterial, viral, and eukaryotic pathogens leverage the host process of autophagy to acquire nutrients that support their growth within infected cells.
Collapse
Affiliation(s)
- Shaun Steele
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina Chapel Hill, NC, USA
| | - Jason Brunton
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina Chapel Hill, NC, USA
| | - Thomas Kawula
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina Chapel Hill, NC, USA
| |
Collapse
|
14
|
Jayaram A, Orfanelli T, Doulaveris G, Linhares IM, Ledger WJ, Witkin SS. Autophagy and female genital tract infections: new insights and research directions. BJOG 2014; 121:801-8. [PMID: 24506514 DOI: 10.1111/1471-0528.12523] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2013] [Indexed: 12/17/2022]
Abstract
Autophagy is a highly conserved process by which defective organelles, non-functional proteins, and intracellular microorganisms become sequestered within structures called autophagosomes, which fuse with lysosomes and the engulfed components are degraded by lysosomal enzymes. In microbial autophagy degraded peptides are used to induce antigen-specific acquired immunity. Viruses, bacteria, fungi, and protozoa have developed strategies to subvert autophagy and/or to use this process to promote their replication and persistence. This review details the mechanisms by which microorganisms that infect the female genital tract and/or are detrimental to pregnancy interact with this host defence mechanism. Based on an understanding of autophagy-related pathological mechanisms, we propose new avenues for research to more effectively prevent and/or treat these infectious diseases.
Collapse
Affiliation(s)
- A Jayaram
- Division of Immunology and Infectious Diseases, Department of Obstetrics and Gynecology, Weill Cornell Medical College, New York, NY, USA
| | | | | | | | | | | |
Collapse
|
15
|
Xu S, Battaglia L, Bao X, Fan H. Chloramphenicol acetyltransferase as a selection marker for chlamydial transformation. BMC Res Notes 2013; 6:377. [PMID: 24060200 PMCID: PMC3849861 DOI: 10.1186/1756-0500-6-377] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/11/2013] [Indexed: 12/04/2022] Open
Abstract
Background Chlamydia is a common bacterial pathogen responsible for many diseases. Methods for transforming this important organism using a β-lactamase as a selection marker have been developed very recently. However, the National Institutes of Health Guidelines for Research Involving Recombinant DNA Molecules do not permit transformation experiments with β-lactamase gene-containing vectors for certain human chlamydial pathogens. Therefore, a different selection marker is urgently needed for transformation of those chlamydiae. Results After transformation of plasmid-free Chlamydia trachomatis with pGFP:SW2, which carries a β-lactamase and a chloramphenicol acetyltransferase gene fused to a green fluorescence protein gene, transformants were obtained by selection with either ampicillin or chloramphenicol. Stable chloramphenicol-resistant, but ampicillin-sensitive, transformants were obtained using a pGFP:SW2 derivative without the β-lactamase. All transformants expressed green fluorescence protein and had glycogen synthesis activity restored. Conclusions Chloramphenicol resistance may be used as a selection marker for genetic experiments in Chlamydia. This eliminates the requirement for the use of β-lactamase, of which dissemination to some C. trachomatis serovars may jeopardize clinical treatment of chlamydial infections in pregnant women. Chloramphenicol acetyltransferase may also serve as a useful secondary selection marker for genetic analyses in β-lactamase-transformed chlamydial strains.
Collapse
Affiliation(s)
- Shuang Xu
- Department of Pharmacology, Rutgers University Robert Wood Johnson Medical School, Piscataway, NJ, USA.
| | | | | | | |
Collapse
|
16
|
Bestebroer J, V'kovski P, Mauthe M, Reggiori F. Hidden behind autophagy: the unconventional roles of ATG proteins. Traffic 2013; 14:1029-41. [PMID: 23837619 PMCID: PMC7169877 DOI: 10.1111/tra.12091] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/03/2013] [Accepted: 07/09/2013] [Indexed: 12/27/2022]
Abstract
Macroautophagy (hereafter referred to as autophagy) is an evolutionarily conserved intracellular catabolic transport route that generally allows the lysosomal degradation of cytoplasmic components, including bulk cytosol, protein aggregates, damaged or superfluous organelles and invading microbes. Target structures are sequestered by double‐membrane vesicles called autophagosomes, which are formed through the concerted action of the autophagy (ATG)‐related proteins. Until recently it was assumed that ATG proteins were exclusively involved in autophagy. A growing number of studies, however, have attributed functions to some of them that are distinct from their classical role in autophagosome biogenesis. Autophagy‐independent roles of the ATG proteins include the maintenance of cellular homeostasis and resistance to pathogens. For example, they assist and enhance the turnover of dead cells and microbes upon their phagocytic engulfment, and inhibit murine norovirus replication. Moreover, bone resorption by osteoclasts, innate immune regulation triggered by cytoplasmic DNA and the ER‐associated degradation regulation all have in common the requirement of a subset of ATG proteins. Microorganisms such as coronaviruses, Chlamydia trachomatis or Brucella abortus have even evolved ways to manipulate autophagy‐independent functions of ATG proteins in order to ensure the completion of their intracellular life cycle. Taken together these novel mechanisms add to the repertoire of functions and extend the number of cellular processes involving the ATG proteins.
Collapse
Affiliation(s)
- Jovanka Bestebroer
- Department of Medical Microbiology, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands; Department of Cell Biology and Institute of Biomembranes, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | | | | | | |
Collapse
|
17
|
Romano JD, Coppens I. Host Organelle Hijackers: a similar modus operandi for Toxoplasma gondii and Chlamydia trachomatis: co-infection model as a tool to investigate pathogenesis. Pathog Dis 2013; 69:72-86. [PMID: 23821471 DOI: 10.1111/2049-632x.12057] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 06/11/2013] [Accepted: 06/11/2013] [Indexed: 12/27/2022] Open
Abstract
The bacterium Chlamydia trachomatis and the protozoan parasite Toxoplasma gondii are the causative agents of chlamydiosis and toxoplasmosis in humans, respectively. Both microorganisms are obligate intracellular pathogens and notorious for extensively modifying the cytoskeletal architecture and the endomembrane system of their host cells to establish productive infections. This review highlights the similar tactics developed by these two pathogens to manipulate their host cell despite their genetic unrelatedness. Using an in vitro cell culture model whereby single fibroblasts are infected by C. trachomatis and T. gondii simultaneously, thus setting up an intracellular competition, we demonstrate that the solutions to the problem of intracellular survival deployed by the parasite and the bacterium may represent an example of convergent evolution, driven by the necessity to acquire nutrients in a hostile environment.
Collapse
Affiliation(s)
- Julia D Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | | |
Collapse
|
18
|
Reggiori F. Autophagy: New Questions from Recent Answers. ISRN MOLECULAR BIOLOGY 2012; 2012:738718. [PMID: 27335669 PMCID: PMC4890908 DOI: 10.5402/2012/738718] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 11/27/2012] [Indexed: 12/11/2022]
Abstract
Macroautophagy (hereafter autophagy) is currently one of the areas of medical life sciences attracting a great interest because of its pathological implications and therapy potentials. The discovery of the autophagy-related genes (ATGs) has been the key event in this research field because their study has led to the acquisition of new knowledge about the mechanism of this transport pathway. In addition, the investigation of these genes in numerous model systems has revealed the central role that autophagy plays in maintaining the cell homeostasis. This process carries out numerous physiological functions, some of which were unpredicted and thus surprising. Here, we will review some of the questions about the mechanism and function of autophagy that still remain unanswered, and new ones that have emerged from the recent discoveries.
Collapse
Affiliation(s)
- Fulvio Reggiori
- Department of Cell Biology and Institute of Biomembranes, University Medical Centre Utrecht, Heidelberglaan 100, Utrecht, The Netherlands
| |
Collapse
|
19
|
Yasir M, Pachikara ND, Bao X, Pan Z, Fan H. Regulation of chlamydial infection by host autophagy and vacuolar ATPase-bearing organelles. Infect Immun 2011; 79:4019-28. [PMID: 21807906 PMCID: PMC3187247 DOI: 10.1128/iai.05308-11] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 07/20/2011] [Indexed: 11/20/2022] Open
Abstract
As arguably the most successful parasite, Chlamydia is an obligate intracellular bacterium replicating inside a vacuole of eukaryotic host cells. The chlamydial vacuole does not fuse with the defense cell organelle lysosome. We previously showed that chlamydial infection increases markers of autophagy, an innate antimicrobial activity requiring lysosomal function. However, the work presented here demonstrates that p62, an autophagy protein that is degraded in lysosomes, either remained unchanged or increased in chlamydia-infected human epithelial, mouse fibroblast, and mouse macrophage cell lines. In addition, the activities of three lysosomal enzymes analyzed were diminished in chlamydia-infected macrophages. Bafilomycin A1 (BafA), a specific inhibitor of vacuolar ATPase (vATPase) required for lysosomal function, increased the growth of the human pathogen Chlamydia trachomatis (L2) in wild-type murine fibroblasts and macrophages but inhibited growth in the autophagy-deficient ATG5(-/-) fibroblasts. BafA exhibited only slight inhibition or no effect on L2 growth in multiple human genital epithelial cell lines. In contrast to L2, the mouse pathogen Chlamydia muridarum (MoPn) was consistently inhibited by BafA in all cell lines examined, regardless of species origin and autophagy status. Finally, L2 but not MoPn grew more efficiently in the ATG5(-/-) cells than in wild-type cells. These results suggest that there are two types of vATPase-bearing organelles that regulate chlamydial infection: one supports chlamydial infection, while the other plays a defensive role through autophagy when cells are artificially infected with certain chlamydiae that have not been adapted to the host species.
Collapse
Affiliation(s)
| | | | | | - Zui Pan
- Department of Physiology and Biophysics, Robert Wood Johnson Medical School, 683 Hoes Lane, Piscataway, New Jersey 08854
| | - Huizhou Fan
- Department of Physiology and Biophysics, Robert Wood Johnson Medical School, 683 Hoes Lane, Piscataway, New Jersey 08854
| |
Collapse
|
20
|
Ouellette SP, Dorsey FC, Moshiach S, Cleveland JL, Carabeo RA. Chlamydia species-dependent differences in the growth requirement for lysosomes. PLoS One 2011; 6:e16783. [PMID: 21408144 PMCID: PMC3050816 DOI: 10.1371/journal.pone.0016783] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Accepted: 01/12/2011] [Indexed: 01/06/2023] Open
Abstract
Genome reduction is a hallmark of obligate intracellular pathogens such as Chlamydia, where adaptation to intracellular growth has resulted in the elimination of genes encoding biosynthetic enzymes. Accordingly, chlamydiae rely heavily on the host cell for nutrients yet their specific source is unclear. Interestingly, chlamydiae grow within a pathogen-defined vacuole that is in close apposition to lysosomes. Metabolically-labeled uninfected host cell proteins were provided as an exogenous nutrient source to chlamydiae-infected cells, and uptake and subsequent labeling of chlamydiae suggested lysosomal degradation as a source of amino acids for the pathogen. Indeed, Bafilomycin A1 (BafA1), an inhibitor of the vacuolar H+/ATPase that blocks lysosomal acidification and functions, impairs the growth of C. trachomatis and C. pneumoniae, and these effects are especially profound in C. pneumoniae. BafA1 induced the marked accumulation of material within the lysosomal lumen, which was due to the inhibition of proteolytic activities, and this response inhibits chlamydiae rather than changes in lysosomal acidification per se, as cathepsin inhibitors also inhibit the growth of chlamydiae. Finally, the addition of cycloheximide, an inhibitor of eukaryotic protein synthesis, compromises the ability of lysosomal inhibitors to block chlamydial growth, suggesting chlamydiae directly access free amino acids in the host cytosol as a preferred source of these nutrients. Thus, chlamydiae co-opt the functions of lysosomes to acquire essential amino acids.
Collapse
Affiliation(s)
- Scot P. Ouellette
- Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College, London, United Kingdom
| | - Frank C. Dorsey
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, United States of America
| | - Simon Moshiach
- Department of Tumor Cell Biology and Genetics, St. Jude Children's Research Hospital, Memphis, Tennessee, United States or America
| | - John L. Cleveland
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, United States of America
| | - Rey A. Carabeo
- Centre for Molecular Microbiology and Infection, Division of Cell and Molecular Biology, Imperial College, London, United Kingdom
- * E-mail:
| |
Collapse
|
21
|
Abstract
Autophagy adjusts cellular biomass and function in response to diverse stimuli, including infection. Autophagy plays specific roles in shaping immune system development, fueling host innate and adaptive immune responses, and directly controlling intracellular microbes as a cell-autonomous innate defense. As an evolutionary counterpoint, intracellular pathogens have evolved to block autophagic microbicidal defense and subvert host autophagic responses for their survival or growth. The ability of eukaryotic pathogens to deploy their own autophagic machinery may also contribute to microbial pathogenesis. Thus, a complex interplay between autophagy and microbial adaptations against autophagy governs the net outcome of host-microbe encounters.
Collapse
|