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Ullah H, Shi X, Taj A, Cheng L, Yan Q, Sha S, Ahmad, Kang J, Haris M, Ma X, Ma Y. Mycobacterium tuberculosis PE_PGRS38 Enhances Intracellular Survival of Mycobacteria by Inhibiting TLR4/NF-κB-Dependent Inflammation and Apoptosis of the Host. BIOLOGY 2024; 13:313. [PMID: 38785795 PMCID: PMC11118070 DOI: 10.3390/biology13050313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/20/2024] [Accepted: 04/27/2024] [Indexed: 05/25/2024]
Abstract
Mycobacterium tuberculosis (Mtb) ranks as the most lethal human pathogen, able to fend off repeated attacks by the immune system or medications. PE_PGRS proteins are hallmarks of the pathogenicity of Mtb and contribute to its antigenic diversity, virulence, and persistence during infection. M. smegmatis is a nonpathogenic mycobacterium that naturally lacks PE_PGRS and is used as a model to express Mtb proteins. PE_PGRS has the capability to evade host immune responses and enhance the intracellular survival of M. smegmatis. Despite the intense investigations into PE_PGRS proteins, their role in tuberculosis remains elusive. We engineered the recombinant M. smegmatis strain Ms-PE_PGRS38. The result shows that PE_PGRS38 is expressed in the cell wall of M. smegmatis. PE_PGRS38 contributes to biofilm formation, confers permeability to the cell wall, and shows variable responses to exogenous stresses. PE_PGRS38 downregulated TLR4/NF-κB signaling in RAW264.7 macrophages and lung tissues of infected mice. In addition, PE_PGRS38 decreased NLRP3-dependent IL-1β release and limited pathogen-mediated inflammasome activity during infection. Moreover, PE_PGRS38 inhibited the apoptosis of RAW264.7 cells by downregulating the expression of apoptotic markers including Bax, cytochrome c, caspase-3, and caspase-9. In a nutshell, our findings demonstrate that PE_PGRS38 is a virulence factor for Mtb that enables recombinant M. smegmatis to survive by resisting and evading the host's immune responses during infection.
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Affiliation(s)
- Hayan Ullah
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (H.U.); (A.T.); (L.C.); (S.S.); (J.K.); (M.H.)
- Department of Microbiology, Dalian Medical University, Dalian 116044, China;
| | - Xiaoxia Shi
- Department of Experimental Teaching Center of Public Health, Dalian Medical University, Dalian 116044, China;
| | - Ayaz Taj
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (H.U.); (A.T.); (L.C.); (S.S.); (J.K.); (M.H.)
| | - Lin Cheng
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (H.U.); (A.T.); (L.C.); (S.S.); (J.K.); (M.H.)
| | - Qiulong Yan
- Department of Microbiology, Dalian Medical University, Dalian 116044, China;
| | - Shanshan Sha
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (H.U.); (A.T.); (L.C.); (S.S.); (J.K.); (M.H.)
| | - Ahmad
- Department of Immunology, Dalian Medical University, Dalian 116044, China;
| | - Jian Kang
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (H.U.); (A.T.); (L.C.); (S.S.); (J.K.); (M.H.)
| | - Muhammad Haris
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (H.U.); (A.T.); (L.C.); (S.S.); (J.K.); (M.H.)
| | - Xiaochi Ma
- Pharmaceutical Research Center, The Second Affiliated Hospital, Dalian Medical University, Dalian 116044, China
| | - Yufang Ma
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian 116044, China; (H.U.); (A.T.); (L.C.); (S.S.); (J.K.); (M.H.)
- Department of Microbiology, Dalian Medical University, Dalian 116044, China;
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Xu A, Yang K, Xu J, Meng X, Liang Q, Huang B, Yang Y, Song H. Mycobacterial PE12 protein promotes bacterial survival through inhibiting cell apoptosis. Vet Microbiol 2024; 288:109922. [PMID: 38086162 DOI: 10.1016/j.vetmic.2023.109922] [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: 06/27/2023] [Revised: 10/03/2023] [Accepted: 11/19/2023] [Indexed: 12/30/2023]
Abstract
Mycobacterial PE_PGRS family proteins play key roles in pathogen-host interaction. However, the function of most PE_PGRS proteins remains unknown. In this study, we characterized the role of PE12 of Mycobacterium bovis (M. bovis) on bacterial growth, bacterial survival, and host cell apoptosis. Transcriptome sequencing of infected THP-1 cells was also performed. Compared to Ms_Vec, we found that M. bovis PE12 did not alter the colony morphology of M. smegmatis. The survival of Ms_PE12 was obviously higher than that of Ms_Vec. Furthermore, PE12 significantly suppressed the apoptosis of THP-1 induced by M. smegmatis infection. Transcriptome analysis results showed that there were 70 downregulated genes in the Ms_PE12 infection group in comparison with the Ms_Vec infection group, and these differentially expressed genes were enriched in 240 downregulated GO terms and 6 KEGG pathways. The downregulated expression genes are involved in cell adhesion, phagocytosis, apoptosis, inflammatory response, glycolysis and transmembrane transporter activity. Taken together, our study reveals that PE12 can suppress apoptosis and inhibit proinflammatory cytokine response. We propose that PE12 is related to macrophage phagocytosis and apoptosis, providing useful information to the pathogenic mechanisms of M. bovis.
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Affiliation(s)
- Ahui Xu
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China-Australia Joint Laboratory for Animal Health Big Data Analytics, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, 666 Wusu Street, Lin'an District, Hangzhou, Zhejiang Province 311300, China
| | - Ke Yang
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China-Australia Joint Laboratory for Animal Health Big Data Analytics, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, 666 Wusu Street, Lin'an District, Hangzhou, Zhejiang Province 311300, China
| | - Jinxia Xu
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China-Australia Joint Laboratory for Animal Health Big Data Analytics, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, 666 Wusu Street, Lin'an District, Hangzhou, Zhejiang Province 311300, China
| | - Xiangmiao Meng
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China-Australia Joint Laboratory for Animal Health Big Data Analytics, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, 666 Wusu Street, Lin'an District, Hangzhou, Zhejiang Province 311300, China
| | - Qiuyun Liang
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China-Australia Joint Laboratory for Animal Health Big Data Analytics, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, 666 Wusu Street, Lin'an District, Hangzhou, Zhejiang Province 311300, China
| | - Bei Huang
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China-Australia Joint Laboratory for Animal Health Big Data Analytics, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, 666 Wusu Street, Lin'an District, Hangzhou, Zhejiang Province 311300, China
| | - Yang Yang
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China-Australia Joint Laboratory for Animal Health Big Data Analytics, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, 666 Wusu Street, Lin'an District, Hangzhou, Zhejiang Province 311300, China.
| | - Houhui Song
- Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Provincial Engineering Research Center for Animal Health Diagnostics & Advanced Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China-Australia Joint Laboratory for Animal Health Big Data Analytics, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, 666 Wusu Street, Lin'an District, Hangzhou, Zhejiang Province 311300, China.
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Rahlwes KC, Dias BR, Campos PC, Alvarez-Arguedas S, Shiloh MU. Pathogenicity and virulence of Mycobacterium tuberculosis. Virulence 2023; 14:2150449. [PMID: 36419223 PMCID: PMC9817126 DOI: 10.1080/21505594.2022.2150449] [Citation(s) in RCA: 32] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, an infectious disease with one of the highest morbidity and mortality rates worldwide. Leveraging its highly evolved repertoire of non-protein and protein virulence factors, Mtb invades through the airway, subverts host immunity, establishes its survival niche, and ultimately escapes in the setting of active disease to initiate another round of infection in a naive host. In this review, we will provide a concise synopsis of the infectious life cycle of Mtb and its clinical and epidemiologic significance. We will also take stock of its virulence factors and pathogenic mechanisms that modulate host immunity and facilitate its spread. Developing a greater understanding of the interface between Mtb virulence factors and host defences will enable progress toward improved vaccines and therapeutics to prevent and treat tuberculosis.
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Affiliation(s)
- Kathryn C. Rahlwes
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Beatriz R.S. Dias
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Priscila C. Campos
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Samuel Alvarez-Arguedas
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Michael U. Shiloh
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA,Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA,CONTACT Michael U. Shiloh
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Guo F, Wei J, Song Y, Li B, Qian Z, Wang X, Wang H, Xu T. Immunological effects of the PE/PPE family proteins of Mycobacterium tuberculosis and related vaccines. Front Immunol 2023; 14:1255920. [PMID: 37841250 PMCID: PMC10569470 DOI: 10.3389/fimmu.2023.1255920] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/25/2023] [Indexed: 10/17/2023] Open
Abstract
Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb), and its incidence and mortality are increasing. The BCG vaccine was developed in the early 20th century. As the most widely administered vaccine in the world, approximately 100 million newborns are vaccinated with BCG every year, which has saved tens of millions of lives. However, due to differences in region and race, the average protective rate of BCG in preventing tuberculosis in children is still not high in some areas. Moreover, because the immune memory induced by BCG will weaken with the increase of age, it is slightly inferior in preventing adult tuberculosis, and BCG revaccination cannot reduce the incidence of tuberculosis again. Research on the mechanism of Mtb and the development of new vaccines against TB are the main strategies for preventing and treating TB. In recent years, Pro-Glu motif-containing (PE) and Pro-Pro-Glu motif-containing (PPE) family proteins have been found to have an increasingly important role in the pathogenesis and chronic protracted infection observed in TB. The development and clinical trials of vaccines based on Mtb antigens are in progress. Herein, we review the immunological effects of PE/PPE proteins and the development of common PE/PPE vaccines.
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Affiliation(s)
- Fangzheng Guo
- Research Center of Laboratory, Bengbu Medical College, Bengbu, China
- Anhui Province Key Laboratory of Immunology in Chronic Diseases , Bengbu Medical College, Bengbu, China
| | - Jing Wei
- Research Center of Laboratory, Bengbu Medical College, Bengbu, China
- Anhui Province Key Laboratory of Immunology in Chronic Diseases , Bengbu Medical College, Bengbu, China
| | - Yamin Song
- Research Center of Laboratory, Bengbu Medical College, Bengbu, China
- Anhui Province Key Laboratory of Immunology in Chronic Diseases , Bengbu Medical College, Bengbu, China
| | - Baiqing Li
- Research Center of Laboratory, Bengbu Medical College, Bengbu, China
- Anhui Province Key Laboratory of Immunology in Chronic Diseases , Bengbu Medical College, Bengbu, China
- Department of Immunology, School of Laboratory, Bengbu Medical College, Bengbu, China
| | - Zhongqing Qian
- Research Center of Laboratory, Bengbu Medical College, Bengbu, China
- Anhui Province Key Laboratory of Immunology in Chronic Diseases , Bengbu Medical College, Bengbu, China
- Department of Immunology, School of Laboratory, Bengbu Medical College, Bengbu, China
| | - Xiaojing Wang
- Anhui Province Key Laboratory of Clinical and Preclinical Research in Respiratory Disease, Bengbu Medical College, Bengbu, China
| | - Hongtao Wang
- Research Center of Laboratory, Bengbu Medical College, Bengbu, China
- Anhui Province Key Laboratory of Immunology in Chronic Diseases , Bengbu Medical College, Bengbu, China
- Department of Immunology, School of Laboratory, Bengbu Medical College, Bengbu, China
| | - Tao Xu
- Research Center of Laboratory, Bengbu Medical College, Bengbu, China
- Anhui Province Key Laboratory of Immunology in Chronic Diseases , Bengbu Medical College, Bengbu, China
- Department of Clinical Laboratory, School of Laboratory, Bengbu Medical College, Bengbu, China
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Anand PK, Saini V, Kaur J, Kumar A, Kaur J. Cell wall and immune modulation by Rv1800 (PPE28) helps M. smegmatis to evade intracellular killing. Int J Biol Macromol 2023; 247:125837. [PMID: 37455004 DOI: 10.1016/j.ijbiomac.2023.125837] [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: 04/03/2023] [Revised: 06/27/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
Rv1800 is predicted as PPE family protein found in pathogenic mycobacteria only. Under acidic stress, the rv1800 gene was expressed in M. tuberculosis H37Ra. In-silico study showed lipase/esterase activity in C-terminus PE-PPE domain having pentapeptide motif with catalytic Ser-Asp-His residue. Full-length Rv1800 and C-terminus PE-PPE domain proteins showed esterase activity with pNP-C4 at the optimum temperature of 40 °C and pH 8.0. However, the N-terminus PPE domain showed no esterase activity, but involved in thermostability of Rv1800 full-length protein. M. smegmatis expressing rv1800 (MS_Rv1800) showed altered colony morphology and a significant resistance to numerous environmental stresses, antibiotics and higher lipid content. In extracellular and membrane fraction, Rv1800 protein was detected, while C terminus PE-PPE was present in cytoplasm, suggesting the role of N-terminus PPE domain in transportation of protein. MS_Rv1800 infected macrophage showed higher intracellular survival and low production of ROS, NO and expression levels of iNOS and pro-inflammatory cytokines, while induced expression of the anti-inflammatory cytokines. The Rv1800, PPE and PE-PPE showed antibody-mediated immunity in MDR-TB and PTB patients. Overall, these results confirmed the esterase activity in the C-terminus and function of N-terminus in thermostabilization and transportation; predicting the role of Rv1800 in immune/lipid modulation to support intracellular mycobacterium survival.
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Affiliation(s)
- Pradeep Kumar Anand
- Department of Biotechnology, BMS Block-1, South Campus, Panjab University, Chandigarh, 160014, India
| | - Varinder Saini
- Department of Pulmonary Medicine, Government Medical College and Hospital, Chandigarh, India
| | - Jasbinder Kaur
- Department of Biochemistry, Government Medical College and Hospital, Chandigarh, India
| | - Arbind Kumar
- Department of Biotechnology, BMS Block-1, South Campus, Panjab University, Chandigarh, 160014, India
| | - Jagdeep Kaur
- Department of Biotechnology, BMS Block-1, South Campus, Panjab University, Chandigarh, 160014, India.
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Anand PK, Kaur J. Rv3539 (PPE63) of Mycobacterium Tuberculosis Promotes Survival of Mycobacterium Smegmatis in Human Macrophages Cell Line via Cell Wall Modulation of Bacteria and Altering Host's Immune Response. Curr Microbiol 2023; 80:267. [PMID: 37401981 DOI: 10.1007/s00284-023-03360-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/31/2023] [Indexed: 07/05/2023]
Abstract
The modulation of host's immune response plays an important role in the intracellular survival of Mycobacterium tuberculosis. The intracellular pathogen counteracts environmental stresses with help of the expression of several genes. The M. tuberculosis genome encodes several immune-modulatory proteins including PE (proline-glutamic acid)/PPE (proline-proline-glutamic acid) superfamily proteins. It is unclear how the unique PE/PPE proteins superfamily contributes to survival under different stress and pathophysiology conditions. Previously, we showed that PPE63 (Rv3539) has C-terminal esterase extension and was localized as a membrane attached and in extracellular compartment. Therefore, the probability of these proteins interacting with the host to modulate the host immune response cannot be ruled out. The physiological role of PPE63 was characterized by expressing the PPE63 in the M. smegmatis, a non-pathogenic strain intrinsically deficient of PPE63. The recombinant M. smegmatis expressing PPE63 altered the colony morphology, lipid composition, and integrity of the cell wall. It provided resistance to multiple hostile environmental stress conditions and several antibiotics. MS_Rv3539 demonstrated higher infection and intracellular survival in comparison to the MS_Vec in the PMA-differentiated THP-1 cells. The decreased intracellular level of ROS, NO, and expression of iNOS was observed in THP-1 cells upon infection with MS_Rv3539 in comparison to MS_Vec. Further, the decrease in expression of pro-inflammatory cytokines like IL-6, TNF-α, and IL-1β and enhanced anti-inflammatory cytokines like IL-10, pointed toward its role in immune modulation. Overall this study suggested the role of Rv3539 in enhanced intracellular survival of M. smegmatis via cell wall modulation and altered immune response of host.
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Affiliation(s)
- Pradeep K Anand
- Department of Biotechnology, Panjab University, BMS Block-1, South Campus, Chandigarh, 160014, India
| | - Jagdeep Kaur
- Department of Biotechnology, Panjab University, BMS Block-1, South Campus, Chandigarh, 160014, India.
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Li W, Yan Z, Zhang N, Zhang Z, Xiang X. Novel role of PE_PGRS47 in the alteration of mycobacterial cell wall integrity and drug resistance. Arch Microbiol 2023; 205:174. [PMID: 37022460 DOI: 10.1007/s00203-023-03515-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 03/11/2023] [Accepted: 03/23/2023] [Indexed: 04/07/2023]
Abstract
The proline-glutamic acid and proline-proline-glutamic acid (PE/PPE) family of proteins is widespread in pathogenic mycobacteria and plays different roles in mycobacterial physiology. While several PE/PPE family proteins have been studied, the exact function of most PE/PPE proteins in the physiology of Mycobacterium tuberculosis (Mtb) remains unknown. PE_PGRS47 belongs to the PE/PPE family of proteins reported to help Mtb evade protective host immune responses. In this study, we demonstrate a novel role of PE_PGRS47. Heterologous expression of the pe_pgrs47 gene in a non-pathogenic Mycobacterium smegmatis, intrinsically deficient of PE_PGRS protein, exhibits modulated colony morphology and cell wall lipid profile leading to a marked susceptibility to multiple antibiotics and environmental stressors. Using ethidium bromide/Nile red uptake assays, Mycobacterium smegmatis expressing PE_PGRS47 showed higher cell wall permeability than the control strain. Overall, these data suggested that PE_PGRS47 is cell surface exposed and influences cell wall integrity and the formation of mycobacterial colonies, ultimately potentiating the efficacy of lethal stresses against mycobacteria.
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Affiliation(s)
- Wu Li
- Key Laboratory of Regional Characteristic Agricultural Resources, College of Life Sciences, Neijiang Normal University, Neijiang, 641100, Sichuan, People's Republic of China.
| | - Zifei Yan
- Key Laboratory of Regional Characteristic Agricultural Resources, College of Life Sciences, Neijiang Normal University, Neijiang, 641100, Sichuan, People's Republic of China
| | - Nan Zhang
- Key Laboratory of Regional Characteristic Agricultural Resources, College of Life Sciences, Neijiang Normal University, Neijiang, 641100, Sichuan, People's Republic of China
| | - Zhiyong Zhang
- Key Laboratory of Regional Characteristic Agricultural Resources, College of Life Sciences, Neijiang Normal University, Neijiang, 641100, Sichuan, People's Republic of China
| | - Xiaohong Xiang
- School of Pharmacy, Chongqing Medical and Pharmaceutical College, Chongqing, 401331, People's Republic of China.
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Witt KD. Role of MHC class I pathways in Mycobacterium tuberculosis antigen presentation. Front Cell Infect Microbiol 2023; 13:1107884. [PMID: 37009503 PMCID: PMC10050577 DOI: 10.3389/fcimb.2023.1107884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 02/23/2023] [Indexed: 03/17/2023] Open
Abstract
MHC class I antigen processing is an underappreciated area of nonviral host–pathogen interactions, bridging both immunology and cell biology, where the pathogen’s natural life cycle involves little presence in the cytoplasm. The effective response to MHC-I foreign antigen presentation is not only cell death but also phenotypic changes in other cells and stimulation of the memory cells ready for the next antigen reoccurrence. This review looks at the MHC-I antigen processing pathway and potential alternative sources of the antigens, focusing on Mycobacterium tuberculosis (Mtb) as an intracellular pathogen that co-evolved with humans and developed an array of decoy strategies to survive in a hostile environment by manipulating host immunity to its own advantage. As that happens via the selective antigen presentation process, reinforcement of the effective antigen recognition on MHC-I molecules may stimulate subsets of effector cells that act earlier and more locally. Vaccines against tuberculosis (TB) could potentially eliminate this disease, yet their development has been slow, and success is limited in the context of this global disease’s spread. This review’s conclusions set out potential directions for MHC-I-focused approaches for the next generation of vaccines.
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Affiliation(s)
- Karolina D. Witt
- Pandemic Sciences Institute, University of Oxford, Oxford, United Kingdom
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- *Correspondence: Karolina D. Witt,
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D'Souza C, Kishore U, Tsolaki AG. The PE-PPE Family of Mycobacterium tuberculosis: Proteins in Disguise. Immunobiology 2023; 228:152321. [PMID: 36805109 DOI: 10.1016/j.imbio.2022.152321] [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: 06/28/2022] [Revised: 12/22/2022] [Accepted: 12/27/2022] [Indexed: 12/31/2022]
Abstract
Mycobacterium tuberculosis has thrived in parallel with humans for millennia, and despite our efforts, M. tuberculosis continues to plague us, currently infecting a third of the world's population. The success of M. tuberculosis has recently been attributed, in part, to the PE-PPE family; a unique collection of 168 proteins fundamentally involved in the pathogenesis of M. tuberculosis. The PE-PPE family proteins have been at the forefront of intense research efforts since their discovery in 1998 and whilst our knowledge and understanding has significantly advanced over the last two decades, many important questions remain to be elucidated. This review consolidates and examines the vast body of existing literature regarding the PE-PPE family proteins, with respect to the latest developments in elucidating their evolution, structure, subcellular localisation, function, and immunogenicity. This review also highlights significant inconsistencies and contradictions within the field. Additionally, possible explanations for these knowledge gaps are explored. Lastly, this review poses many important questions, which need to be addressed to complete our understanding of the PE-PPE family, as well as highlighting the challenges associated with studying this enigmatic family of proteins. Further research into the PE-PPE family, together with technological advancements in genomics and proteomics, will undoubtedly improve our understanding of the pathogenesis of M. tuberculosis, as well as identify key targets/candidates for the development of novel drugs, diagnostics, and vaccines.
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Affiliation(s)
- Christopher D'Souza
- Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, United Kingdom
| | - Uday Kishore
- Department of Veterinary Medicine, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Anthony G Tsolaki
- Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge UB8 3PH, United Kingdom.
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Matsumura K, Takaki S, Kirikae T. Mycobacterial protein PE_PGRS30 induces macrophage apoptosis through prohibitin 2 mitochondrial function interference. Front Microbiol 2023; 14:1080369. [PMID: 36778852 PMCID: PMC9911437 DOI: 10.3389/fmicb.2023.1080369] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/10/2023] [Indexed: 01/28/2023] Open
Abstract
PE_PGRS30 belongs to the PE_PGRS protein family and is characterized by a conserved Pro-Glu (PE) domain and a typically polymorphic GC-rich sequence (PGRS) domain. PE_PGRS30 is a virulence factor of Mycobacterium tuberculosis that induces macrophage cell death. We found that RAW264.7 cells and murine alveolar macrophages underwent apoptosis in response to PE_PGRS30. The host protein prohibitin 2 (PHB2) was identified as a target molecule. PE_PGRS30 and PHB2 interact via the PGRS domain and mitochondrial targeting sequence, respectively. PHB2 overexpression reduced macrophage apoptosis in response to PE_PGRS30. PE_PGRS30 co-localized with PHB2, not in mitochondria, but in lysosomes. The maintenance of mitochondrial structure by PHB2 was impaired in response to the PGRS domain. These results indicated that PE_PGRS30 reduces PHB2 in mitochondria, resulting in mitochondrial dysfunction and cellular apoptosis.
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Affiliation(s)
- Kazunori Matsumura
- Department of Immune Regulation, Research Institute, National Center for Global Health and Medicine, Chiba, Japan
| | - Satoshi Takaki
- Department of Immune Regulation, Research Institute, National Center for Global Health and Medicine, Chiba, Japan
| | - Teruo Kirikae
- Graduate School of Medicine, Juntendo University, Tokyo, Japan,*Correspondence: Teruo Kirikae,
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The Mycobacterium tuberculosis PE_PGRS Protein Family Acts as an Immunological Decoy to Subvert Host Immune Response. Int J Mol Sci 2022; 23:ijms23010525. [PMID: 35008950 PMCID: PMC8745494 DOI: 10.3390/ijms23010525] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/03/2021] [Accepted: 12/15/2021] [Indexed: 02/04/2023] Open
Abstract
Mycobacterium tuberculosis (M.tb) is a successful pathogen that can reside within the alveolar macrophages of the host and can survive in a latent stage. The pathogen has evolved and developed multiple strategies to resist the host immune responses. M.tb escapes from host macrophage through evasion or subversion of immune effector functions. M.tb genome codes for PE/PPE/PE_PGRS proteins, which are intrinsically disordered, redundant and antigenic in nature. These proteins perform multiple functions that intensify the virulence competence of M.tb majorly by modulating immune responses, thereby affecting immune mediated clearance of the pathogen. The highly repetitive, redundant and antigenic nature of PE/PPE/PE_PGRS proteins provide a critical edge over other M.tb proteins in terms of imparting a higher level of virulence and also as a decoy molecule that masks the effect of effector molecules, thereby modulating immuno-surveillance. An understanding of how these proteins subvert the host immunological machinery may add to the current knowledge about M.tb virulence and pathogenesis. This can help in redirecting our strategies for tackling M.tb infections.
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PGRS Domain of Rv0297 of Mycobacterium tuberculosis Functions in A Calcium Dependent Manner. Int J Mol Sci 2021; 22:ijms22179390. [PMID: 34502303 PMCID: PMC8430768 DOI: 10.3390/ijms22179390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/12/2021] [Accepted: 03/24/2021] [Indexed: 01/04/2023] Open
Abstract
Mycobacterium tuberculosis (M.tb), the pathogen causing tuberculosis, is a major threat to human health worldwide. Nearly 10% of M.tb genome encodes for a unique family of PE/PPE/PGRS proteins present exclusively in the genus Mycobacterium. The functions of most of these proteins are yet unexplored. The PGRS domains of these proteins have been hypothesized to consist of Ca2+ binding motifs that help these intrinsically disordered proteins to modulate the host cellular responses. Ca2+ is an important secondary messenger that is involved in the pathogenesis of tuberculosis in diverse ways. This study presents the calcium-dependent function of the PGRS domain of Rv0297 (PE_PGRS5) in M.tb virulence and pathogenesis. Tandem repeat search revealed the presence of repetitive Ca2+ binding motifs in the PGRS domain of the Rv0297 protein (Rv0297PGRS). Molecular Dynamics simulations and fluorescence spectroscopy revealed Ca2+ dependent stabilization of the Rv0297PGRS protein. Calcium stabilized Rv0297PGRS enhances the interaction of Rv0297PGRS with surface localized Toll like receptor 4 (TLR4) of macrophages. The Ca2+ stabilized binding of Rv0297PGRS with the surface receptor of macrophages enhances its downstream consequences in terms of Nitric Oxide (NO) production and cytokine release. Thus, this study points to hitherto unidentified roles of calcium-modulated PE_PGRS proteins in the virulence of M.tb. Understanding the pathogenic potential of Ca2+ dependent PE_PGRS proteins can aid in targeting these proteins for therapeutic interventions.
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Xie Y, Zhou Y, Liu S, Zhang XL. PE_PGRS: Vital proteins in promoting mycobacterial survival and modulating host immunity and metabolism. Cell Microbiol 2020; 23:e13290. [PMID: 33217152 DOI: 10.1111/cmi.13290] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/04/2020] [Accepted: 11/08/2020] [Indexed: 12/20/2022]
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis (M. tb), is the leading infectious cause of mortality worldwide. One of the key reasons for M. tb pathogenesis is the capability of M. tb to evade immune elimination and survive in macrophage, eventually causing chronic infection. However the pathogenicity mechanism of M. tb is not unclear yet, and thus diagnosis and therapy for TB remains a challenge. The genome of M. tb, encodes a unique protein family known as the PGRS family, with largely unexplored functions. Recently, an increasing number of reports have shown that the PE_PGRS proteins play critical roles in bacterial pathogenesis and immune evasion. The PE_PGRS protein family, characterized by a special N-terminal PE (Pro (P)-Glu (E) motif) domain and a C-terminal PGRS (Polymorphic GC-rich Repetitive Sequences) domain, is restricted mainly to pathogenic mycobacteria. Here we summarize current literature on the PE_PGRS as vital proteins in promoting bacterial survival and modulating host immunity, cell death and metabolism. We also highlight the potential of PE_PGRS as novel targets of anti-mycobacterial interventions for TB control.
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Affiliation(s)
- Yan Xie
- Hubei Province Key Laboratory of Allergy and Immunology, Department of Allergy Zhongnan Hospital, Department of Immunology Wuhan University School of Basic Medical Sciences, Wuhan, China.,State Key Laboratory of Virology, Frontier Science Center for Immunology and Metabolism, Wuhan University School of Medicine, Wuhan, China
| | - Yidan Zhou
- Department of Microbiology, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA
| | - Sheng Liu
- Hubei Province Key Laboratory of Allergy and Immunology, Department of Allergy Zhongnan Hospital, Department of Immunology Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Xiao-Lian Zhang
- Hubei Province Key Laboratory of Allergy and Immunology, Department of Allergy Zhongnan Hospital, Department of Immunology Wuhan University School of Basic Medical Sciences, Wuhan, China.,State Key Laboratory of Virology, Frontier Science Center for Immunology and Metabolism, Wuhan University School of Medicine, Wuhan, China
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14
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LPS restores protective immunity in macrophages against Mycobacterium tuberculosis via autophagy. Mol Immunol 2020; 124:18-24. [DOI: 10.1016/j.molimm.2020.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 04/24/2020] [Accepted: 05/03/2020] [Indexed: 12/12/2022]
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15
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Yu X, Feng J, Huang L, Gao H, Liu J, Bai S, Wu B, Xie J. Molecular Basis Underlying Host Immunity Subversion by Mycobacterium tuberculosis PE/PPE Family Molecules. DNA Cell Biol 2019; 38:1178-1187. [PMID: 31580738 DOI: 10.1089/dna.2019.4852] [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: 12/13/2022] Open
Abstract
Mycobacterium tuberculosis proline-glutamic acid (PE)/proline-proline-glutamic acid (PPE) family proteins, with >160 members, are crucial for virulence, cell wall, host cell fate, host Th1/Th2 balance, and CD8+ T cell recognition. Ca2+ signaling is involved in PE/PPE protein-mediated host-pathogen interaction. PE/PPE proteins also function in heme utilization and nitric oxide production. PE/PPE family proteins are intensively pursued as diagnosis biomarkers and vaccine components.
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Affiliation(s)
- Xiaowen Yu
- Chongqing Key Laboratory of Traditional Chinese Medicine to Prevent and Treat Autoimmune Diseases, Chongqing, P.R. China
| | - Jing Feng
- Chongqing Key Laboratory of Traditional Chinese Medicine to Prevent and Treat Autoimmune Diseases, Chongqing, P.R. China
| | - Lu Huang
- Department of Pathology, Xinqiao Hospital, Army Medical University, Chongqing, P.R. China
| | - Hongyan Gao
- Chongqing Key Laboratory of Traditional Chinese Medicine to Prevent and Treat Autoimmune Diseases, Chongqing, P.R. China
| | - Jinkun Liu
- Chongqing Key Laboratory of Traditional Chinese Medicine to Prevent and Treat Autoimmune Diseases, Chongqing, P.R. China
| | - Shutong Bai
- Chongqing Key Laboratory of Traditional Chinese Medicine to Prevent and Treat Autoimmune Diseases, Chongqing, P.R. China
| | - Bin Wu
- Chongqing Key Laboratory of Traditional Chinese Medicine to Prevent and Treat Autoimmune Diseases, Chongqing, P.R. China
| | - Jianping Xie
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing, P.R. China
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Sharma D, Poonam, Shrivastava R, Bisht GS. In Vitro Efficacy of Lipid Conjugated Peptidomimetics Against Mycobacterium smegmatis. Int J Pept Res Ther 2019. [DOI: 10.1007/s10989-019-09859-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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PE17 protein from Mycobacterium tuberculosis enhances Mycobacterium smegmatis survival in macrophages and pathogenicity in mice. Microb Pathog 2019; 126:63-73. [DOI: 10.1016/j.micpath.2018.10.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/22/2018] [Accepted: 10/22/2018] [Indexed: 01/26/2023]
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18
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De Maio F, Battah B, Palmieri V, Petrone L, Corrente F, Salustri A, Palucci I, Bellesi S, Papi M, Rubino S, Sali M, Goletti D, Sanguinetti M, Manganelli R, De Spirito M, Delogu G. PE_PGRS3 of Mycobacterium tuberculosis is specifically expressed at low phosphate concentration, and its arginine-rich C-terminal domain mediates adhesion and persistence in host tissues when expressed in Mycobacterium smegmatis. Cell Microbiol 2018; 20:e12952. [PMID: 30192424 DOI: 10.1111/cmi.12952] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 08/22/2018] [Accepted: 08/28/2018] [Indexed: 12/14/2022]
Abstract
PE_PGRSs of Mycobacterium tuberculosis (Mtb) represent a family of complex and peculiar proteins whose role and function remain elusive. In this study, we investigated PE_PGRS3 and PE_PGRS4, two highly homologous PE_PGRSs encoded by two contiguous genes in the Mtb genome. Using a gene-reporter system in Mycobacterium smegmatis (Ms) and transcriptional analysis in Mtb, we show that PE_PGRS3, but not PE_PGRS4, is specifically expressed under low phosphate concentrations. Interestingly, PE_PGRS3, but not PE_PGRS4, has a unique, arginine-rich C-terminal domain of unknown function. Heterologous expression of PE_PGRS3 in Ms was used to demonstrate cellular localisation of the protein on the mycobacterial surface, where it significantly affects net surface charge. Moreover, expression of full-length PE_PGRS3 enhanced adhesion of Ms to murine macrophages and human epithelial cells and improved bacterial persistence in spleen tissue following infection in mice. Expression of the PE_PGRS3 functional deletion mutant lacking the C-terminal domain in Ms did not enhance adhesion to host cells, showing a phenotype similar to the Ms parental strain. Interestingly, enhanced persistence of Ms expressing PE_PGRS3 did not correlate with increased concentrations of inflammatory cytokines. These results point to a critical role for the ≈ 80 amino acids long, arginine-rich C-terminal domain of PE_PGRS3 in tuberculosis pathogenesis.
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Affiliation(s)
- Flavio De Maio
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Basem Battah
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy.,Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Valentina Palmieri
- Institute of Physics, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Linda Petrone
- Translational Research Unit, Department of Epidemiology and Preclinical Research, National Institute for Infectious Diseases, Rome, Italy
| | - Francesco Corrente
- Institute of Haematology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Alessandro Salustri
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ivana Palucci
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Silvia Bellesi
- Institute of Haematology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Massimiliano Papi
- Institute of Physics, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Salvatore Rubino
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Michela Sali
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Delia Goletti
- Translational Research Unit, Department of Epidemiology and Preclinical Research, National Institute for Infectious Diseases, Rome, Italy
| | - Maurizio Sanguinetti
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - Marco De Spirito
- Institute of Physics, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
| | - Giovanni Delogu
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli, IRCCS - Università Cattolica del Sacro Cuore, Rome, Italy
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Homan EJ, Bremel RD. A Role for Epitope Networking in Immunomodulation by Helminths. Front Immunol 2018; 9:1763. [PMID: 30108588 PMCID: PMC6079203 DOI: 10.3389/fimmu.2018.01763] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/17/2018] [Indexed: 12/19/2022] Open
Abstract
Helminth infections, by nematodes, trematodes, or cestodes, can lead to the modulation of host immune responses. This allows long-duration parasite infections and also impacts responses to co-infections. Surface, secreted, excreted, and shed proteins are thought to play a major role in modulation. A commonly reported feature of such immune modulation is the role of T regulatory (Treg) cells and IL-10. Efforts to identify helminth proteins, which cause immunomodulation, have identified candidates but not provided clarity as to a uniform mechanism driving modulation. In this study, we applied a bioinformatics systems approach, allowing us to analyze predicted T-cell epitopes of 17 helminth species and the responses to their surface proteins. In addition to major histocompatibility complex (MHC) binding, we analyzed amino acid motifs that would be recognized by T-cell receptors [T-cell-exposed motifs (TCEMs)]. All the helminth species examined have, within their surface proteins, peptides, which combine very common TCEMs with predicted high affinity binding to many human MHC alleles. This combination of features would result in large cognate T cell and a high probability of eliciting Treg responses. The TCEMs, which determine recognition by responding T-cell clones, are shared to a high degree between helminth species and with Plasmodium falciparum and Mycobacterium tuberculosis, both common co-infecting organisms. The implication of our observations is not only that Treg cells play a significant role in helminth-induced immune modulation but also that the epitope specificities of Treg responses are shared across species and genera of helminth. Hence, the immune response to a given helminth cannot be considered in isolation but rather forms part of an epitope ecosystem, or microenvironment, in which potentially immunosuppressive peptides in the helminth network via their common T-cell receptor recognition signals with T-cell epitopes in self proteins, microbiome, other helminths, and taxonomically unrelated pathogens. Such a systems approach provides a high-level view of the antigen-immune system signaling dynamics that may bias a host's immune response to helminth infections toward immune modulation. It may indicate how helminths have evolved to select for peptides that favor long-term parasite host coexistence.
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Ates LS, Sayes F, Frigui W, Ummels R, Damen MPM, Bottai D, Behr MA, van Heijst JWJ, Bitter W, Majlessi L, Brosch R. RD5-mediated lack of PE_PGRS and PPE-MPTR export in BCG vaccine strains results in strong reduction of antigenic repertoire but little impact on protection. PLoS Pathog 2018; 14:e1007139. [PMID: 29912964 PMCID: PMC6023246 DOI: 10.1371/journal.ppat.1007139] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/28/2018] [Accepted: 06/05/2018] [Indexed: 01/03/2023] Open
Abstract
Tuberculosis is the deadliest infectious disease worldwide. Although the BCG vaccine is widely used, it does not efficiently protect against pulmonary tuberculosis and an improved tuberculosis vaccine is therefore urgently needed. Mycobacterium tuberculosis uses different ESX/Type VII secretion (T7S) systems to transport proteins important for virulence and host immune responses. We recently reported that secretion of T7S substrates belonging to the mycobacteria-specific Pro-Glu (PE) and Pro-Pro-Glu (PPE) proteins of the PGRS (polymorphic GC-rich sequences) and MPTR (major polymorphic tandem repeat) subfamilies required both a functional ESX-5 system and a functional PPE38/71 protein for secretion. Inactivation of ppe38/71 and the resulting loss of PE_PGRS/PPE-MPTR secretion were linked to increased virulence of M. tuberculosis strains. Here, we show that a predicted total of 89 PE_PGRS/PPE-MPTR surface proteins are not exported by certain animal-adapted strains of the M. tuberculosis complex including M. bovis. This Δppe38/71-associated secretion defect therefore also occurs in the M. bovis-derived tuberculosis vaccine BCG and could be partially restored by introduction of the M. tuberculosis ppe38-locus. Epitope mapping of the PPE-MPTR protein PPE10, further allowed us to monitor T-cell responses in splenocytes from BCG/M. tuberculosis immunized mice, confirming the dependence of PPE10-specific immune-induction on ESX-5/PPE38-mediated secretion. Restoration of PE_PGRS/PPE-MPTR secretion in recombinant BCG neither altered global antigenic presentation or activation of innate immune cells, nor protective efficacy in two different mouse vaccination-infection models. This unexpected finding stimulates a reassessment of the immunomodulatory properties of PE_PGRS/PPE-MPTR proteins, some of which are contained in vaccine formulations currently in clinical evaluation. One of the major findings of the pioneering Mycobacterium tuberculosis H37Rv genome sequencing project was the identification of the highly abundant PE and PPE proteins, named after their N-terminal motifs Pro–Glu (PE) or Pro–Pro–Glu (PPE). Within the 20 years of research since then, many claims were made that PE/PPE proteins, including the two large subgroups encoded by repetitive sequences with very high GC content (PE_PGRS and PPE-MPTR families), are exported to the bacterial surface or beyond, and show broad immunomodulatory impact on host-pathogen interaction. We thus screened strains from different branches of the M. tuberculosis complex, including the attenuated Mycobacterium bovis BCG vaccine strains, for their capacity to export PE_PGRS/PPE-MPTR proteins. Strikingly, we found that BCG strains were unable to export the plethora of PE_PGRS/PPE-MPTR proteins due to the absence of the region of difference RD5, which in M. tuberculosis encodes PPE38, required for PE_PGRS/PPE-MPTR export. Surprisingly, the restoration of PE_PGRS/PPE-MPTR export by genetic complementation in recombinant BCG did not result in immunomodulatory changes or altered protection in mouse models. Our results thus put into perspective the numerous reports on virulence-associated immunomodulatory impact of individual PE_PGRS and PPE-MPTR proteins and open novel questions on their biological function(s).
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Affiliation(s)
- Louis S. Ates
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- * E-mail: (LSA); (RB)
| | - Fadel Sayes
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
| | - Wafa Frigui
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
| | - Roy Ummels
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands
| | - Merel P. M. Damen
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicine & Systems, Vrije Universiteit, Amsterdam, the Netherlands
| | - Daria Bottai
- University of Pisa, Department of Biology, Pisa, Italy
| | - Marcel A. Behr
- McGill International TB Centre, Infectious Diseases and Immunity in Global Health Program at the McGill University Health Centre Research Institute, Montreal, Canada
| | - Jeroen W. J. van Heijst
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicine & Systems, Vrije Universiteit, Amsterdam, the Netherlands
| | - Laleh Majlessi
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
| | - Roland Brosch
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
- * E-mail: (LSA); (RB)
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Mycobacterium tuberculosis PE_PGRS18 enhances the intracellular survival of M. smegmatis via altering host macrophage cytokine profiling and attenuating the cell apoptosis. Apoptosis 2018; 22:502-509. [PMID: 27987050 DOI: 10.1007/s10495-016-1336-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Mycobacterium tuberculosis PE/PPE family proteins, named after the presence of conserved PE (Pro-Glu) and PPE (Pro-Pro-Glu) domains at N-terminal, are prevalent in M. tuberculosis genome. The function of most PE/PPE family proteins remains elusive. To characterize the function of PE_PGRS18, the encoding gene was heterologously expressed in M. smegmatis, a nonpathogenic mycobacterium. The recombinant PE_PGRS18 is cell wall associated. M. smegmatis PE_PGRS18 recombinant showed differential response to stresses and altered the production of host cytokines IL-6, IL-1β, IL-12p40 and IL-10, as well as enhanced survival within macrophages largely via attenuating the apoptosis of macrophages. In summary, the study firstly unveiled the role of PE_PGRS18 in physiology and pathogenesis of mycobacterium.
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Yeruva VC, Kulkarni A, Khandelwal R, Sharma Y, Raghunand TR. The PE_PGRS Proteins of Mycobacterium tuberculosis Are Ca2+ Binding Mediators of Host–Pathogen Interaction. Biochemistry 2016; 55:4675-87. [DOI: 10.1021/acs.biochem.6b00289] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Veena C. Yeruva
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Apoorva Kulkarni
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Radhika Khandelwal
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Yogendra Sharma
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
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