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Liang Y, Wang H, Sun K, Sun J, Soong L. Lack of the IFN-γ signal leads to lethal Orientia tsutsugamushi infection in mice with skin eschar lesions. PLoS Pathog 2024; 20:e1012020. [PMID: 38743761 PMCID: PMC11125519 DOI: 10.1371/journal.ppat.1012020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 05/24/2024] [Accepted: 04/30/2024] [Indexed: 05/16/2024] Open
Abstract
Scrub typhus is an acute febrile disease due to Orientia tsutsugamushi (Ot) infection and can be life-threatening with organ failure, hemorrhage, and fatality. Yet, little is known as to how the host reacts to Ot bacteria at early stages of infection; no reports have addressed the functional roles of type I versus type II interferon (IFN) responses in scrub typhus. In this study, we used comprehensive intradermal (i.d.) inoculation models and two clinically predominant Ot strains (Karp and Gilliam) to uncover early immune events. Karp infection induced sequential expression of Ifnb and Ifng in inflamed skin and draining lymph nodes at days 1 and 3 post-infection. Using double Ifnar1-/-Ifngr1-/- and Stat1-/- mice, we found that deficiency in IFN/STAT1 signaling resulted in lethal infection with profound pathology and skin eschar lesions, which resembled to human scrub typhus. Further analyses demonstrated that deficiency in IFN-γ, but not IFN-I, resulted in impaired NK cell and macrophage activation and uncontrolled bacterial growth and dissemination, leading to metabolic dysregulation, excessive inflammatory cell infiltration, and exacerbated tissue damage. NK cells were found to be the major cellular source of innate IFN-γ, contributing to the initial Ot control in the draining lymph nodes. In vitro studies with dendritic cell cultures revealed a superior antibacterial effect offered by IFN-γ than IFN-β. Comparative in vivo studies with Karp- and Gilliam-infection revealed a crucial role of IFN-γ signaling in protection against progression of eschar lesions and Ot infection lethality. Additionally, our i.d. mouse models of lethal infection with eschar lesions are promising tools for immunological study and vaccine development for scrub typhus.
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Affiliation(s)
- Yuejin Liang
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Hui Wang
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Keer Sun
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jiaren Sun
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lynn Soong
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
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Xu Y, Jia B, Li J, Li Q, Luo C. The Interplay between Ferroptosis and Neuroinflammation in Central Neurological Disorders. Antioxidants (Basel) 2024; 13:395. [PMID: 38671843 PMCID: PMC11047682 DOI: 10.3390/antiox13040395] [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: 03/11/2024] [Revised: 03/23/2024] [Accepted: 03/25/2024] [Indexed: 04/28/2024] Open
Abstract
Central neurological disorders are significant contributors to morbidity, mortality, and long-term disability globally in modern society. These encompass neurodegenerative diseases, ischemic brain diseases, traumatic brain injury, epilepsy, depression, and more. The involved pathogenesis is notably intricate and diverse. Ferroptosis and neuroinflammation play pivotal roles in elucidating the causes of cognitive impairment stemming from these diseases. Given the concurrent occurrence of ferroptosis and neuroinflammation due to metabolic shifts such as iron and ROS, as well as their critical roles in central nervous disorders, the investigation into the co-regulatory mechanism of ferroptosis and neuroinflammation has emerged as a prominent area of research. This paper delves into the mechanisms of ferroptosis and neuroinflammation in central nervous disorders, along with their interrelationship. It specifically emphasizes the core molecules within the shared pathways governing ferroptosis and neuroinflammation, including SIRT1, Nrf2, NF-κB, Cox-2, iNOS/NO·, and how different immune cells and structures contribute to cognitive dysfunction through these mechanisms. Researchers' findings suggest that ferroptosis and neuroinflammation mutually promote each other and may represent key factors in the progression of central neurological disorders. A deeper comprehension of the common pathway between cellular ferroptosis and neuroinflammation holds promise for improving symptoms and prognosis related to central neurological disorders.
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Affiliation(s)
- Yejia Xu
- Department of Forensic Medicine, School of Basic Medicine and Biological Sciences, Soochow University, Suzhou 215123, China
- Hebei Key Laboratory of Forensic Medicine, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China
| | - Bowen Jia
- Department of Forensic Medicine, School of Basic Medicine and Biological Sciences, Soochow University, Suzhou 215123, China
| | - Jing Li
- Department of Forensic Medicine, School of Basic Medicine and Biological Sciences, Soochow University, Suzhou 215123, China
| | - Qianqian Li
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming 650500, China
- School of Forensic Medicine, Wannan Medical College, Wuhu 241002, China
| | - Chengliang Luo
- Department of Forensic Medicine, School of Basic Medicine and Biological Sciences, Soochow University, Suzhou 215123, China
- Hebei Key Laboratory of Forensic Medicine, College of Forensic Medicine, Hebei Medical University, Shijiazhuang 050017, China
- NHC Key Laboratory of Drug Addiction Medicine, Department of Forensic Medicine, School of Forensic Medicine, Kunming Medical University, Kunming 650500, China
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Han S, Yang S, Wang Y, Xu Y. Case Report: Encephalitis with Initial Manifestation of Orientia Tsutsugamushi Infection Detected by Metagenomic Next-Generation Sequencing. Infect Drug Resist 2024; 17:749-760. [PMID: 38433784 PMCID: PMC10906725 DOI: 10.2147/idr.s450693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 02/07/2024] [Indexed: 03/05/2024] Open
Abstract
Purpose Scrub typhus, caused by Orientia tsutsugamushi, is characterized by fever, eschars, lymphadenopathy, and rash. The absence of eschars in some cases makes it difficult to distinguish it from other diseases, complicating the diagnosis process. Atypical Scrub typhus is difficult to diagnose and often leads to delayed treatment. Therefore, early diagnosis and treatment through effective detection methods have high clinical value. Here, a case of scrub typhus with encephalitis symptoms is reported. Patients and Methods A 64-year-old man and mNGS testing. Results A 64-year-old man developed cough, headache, and fever, dismissing it as a respiratory tract infection. Initial treatment with cephalosporin antibiotics had minimal effect. Admission to the respiratory department showed inflammation in blood tests. Subsequent CT and further treatment provided no improvement. Multidisciplinary discussions and neurology department guidance were conducted to consider the suspected diagnosis of encephalitis in the patient. After improving the mNGS detection, the patient was diagnosed with "Orientia tsutsugamushi encephalitis". After treatment with doxycycline, the patient's symptoms were alleviated. He remained afebrile in follow-up and adhered well to medical advice. Conclusion Our case demonstrates that it is difficult to distinguish Orientia tsutsugamushi encephalitis from central nervous system infectious diseases such as meningitis and encephalitis using conventional diagnostic methods, which may affect the treatment plan for the disease. mNGS is a useful and valuable method for early diagnosis of scrub typhus.
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Affiliation(s)
- Song Han
- The Second Hospital of Shandong University, Cheeloo College of Medicine of Shandong University, Shandong University, Jinan, 250033, People’s Republic of China
| | - Suge Yang
- The Second Hospital of Shandong University, Cheeloo College of Medicine of Shandong University, Shandong University, Jinan, 250033, People’s Republic of China
| | - Yun Wang
- Department of Neurology Medicine, The Second Hospital of Shandong University, Cheeloo College of Medicine of Shandong University, Shandong University, Jinan, 250033, People’s Republic of China
| | - Yingying Xu
- Department of Neurology Medicine, The Second Hospital of Shandong University, Cheeloo College of Medicine of Shandong University, Shandong University, Jinan, 250033, People’s Republic of China
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Thiriot JD, Liang Y, Gonzales C, Sun J, Yu X, Soong L. Differential cellular immune responses against Orientia tsutsugamushi Karp and Gilliam strains following acute infection in mice. PLoS Negl Trop Dis 2023; 17:e0011445. [PMID: 38091346 PMCID: PMC10752558 DOI: 10.1371/journal.pntd.0011445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/27/2023] [Accepted: 12/06/2023] [Indexed: 12/28/2023] Open
Abstract
Scrub typhus is a leading cause of febrile illness in endemic countries due to infection with Orientia tsutsugamushi (Ot), a seriously understudied intracellular bacterium. Pulmonary involvement associated with vascular parasitism in patients is common and can develop into life threatening interstitial pneumonia. The diverse antigenicity of Ot genotypes and inter-strain differences in genome content are connected to varied virulence and clinical outcomes; however, detailed studies of strain-related pulmonary immune responses in human patients or small animal models of infection are lacking. In this study, we have used two clinically prevalent bacterial strains (Karp and Gilliam) to reveal cellular immune responses in inflamed lungs and potential biomarkers of disease severity. The results demonstrate that outbred CD-1 mice are highly susceptible to both Karp and Gilliam strains; however, C57BL/6 (B6) mice were susceptible to Karp, but resistant to Gilliam (with self-limiting infection), corresponding to their tissue bacterial burdens and lung pathological changes. Multicolor flow cytometric analyses of perfused B6 mouse lungs revealed robust and sustained influx and activation of innate immune cells (macrophages, neutrophils, and NK cells), followed by CD4+ and CD8+ T cells, during Karp infection, but such responses were greatly attenuated during Gilliam infection. The robust cellular responses in Karp-infected B6 mice positively correlated with significantly early and high levels of serum cytokine/chemokine protein levels (CXCL1, CCL2/3/5, and G-CSF), as well as pulmonary gene expression (Cxcl1/2, Ccl2/3/4, and Ifng). In vitro infection of B6 mouse-derived primary macrophages also revealed bacterial strain-dependent immune gene expression profiles. This study provided the lines of evidence that highlighted differential tissue cellular responses against Karp vs. Gilliam infection, offering a framework for future investigation of Ot strain-related mechanisms of disease pathogenesis vs. infection control.
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Affiliation(s)
- Joseph D. Thiriot
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yuejin Liang
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Casey Gonzales
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jiaren Sun
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Xiaoying Yu
- Department of Biostatistics & Data Science, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lynn Soong
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infection and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
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