1
|
Jayaraman A, Walachowski S, Bosmann M. The complement system: A key player in the host response to infections. Eur J Immunol 2024:e2350814. [PMID: 39188171 DOI: 10.1002/eji.202350814] [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: 03/22/2024] [Revised: 08/13/2024] [Accepted: 08/14/2024] [Indexed: 08/28/2024]
Abstract
Infections are one of the most significant healthcare and economic burdens across the world as underscored by the recent coronavirus pandemic. Moreover, with the increasing incidence of antimicrobial resistance, there is an urgent need to better understand host-pathogen interactions to design effective treatment strategies. The complement system is a key arsenal of the host defense response to pathogens and bridges both innate and adaptive immunity. However, in the contest between pathogens and host defense mechanisms, the host is not always victorious. Pathogens have evolved several approaches, including co-opting the host complement regulators to evade complement-mediated killing. Furthermore, deficiencies in the complement proteins, both genetic and therapeutic, can lead to an inefficient complement-mediated pathogen eradication, rendering the host more susceptible to certain infections. On the other hand, overwhelming infection can provoke fulminant complement activation with uncontrolled inflammation and potentially fatal tissue and organ damage. This review presents an overview of critical aspects of the complement-pathogen interactions during infection and discusses perspectives on designing therapies to mitigate complement dysfunction and limit tissue injury.
Collapse
Affiliation(s)
- Archana Jayaraman
- Department of Medicine, Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Sarah Walachowski
- Department of Medicine, Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Markus Bosmann
- Department of Medicine, Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| |
Collapse
|
2
|
Kulkarni DH, Starick M, Aponte Alburquerque R, Kulkarni HS. Local complement activation and modulation in mucosal immunity. Mucosal Immunol 2024; 17:739-751. [PMID: 38838816 DOI: 10.1016/j.mucimm.2024.05.006] [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: 01/01/2024] [Revised: 05/24/2024] [Accepted: 05/29/2024] [Indexed: 06/07/2024]
Abstract
The complement system is an evolutionarily conserved arm of innate immunity, which forms one of the first lines of host response to pathogens and assists in the clearance of debris. A deficiency in key activators/amplifiers of the cascade results in recurrent infection, whereas a deficiency in regulating the cascade predisposes to accelerated organ failure, as observed in colitis and transplant rejection. Given that there are over 60 proteins in this system, it has become an attractive target for immunotherapeutics, many of which are United States Food and Drug Administration-approved or in multiple phase 2/3 clinical trials. Moreover, there have been key advances in the last few years in the understanding of how the complement system operates locally in tissues, independent of its activities in circulation. In this review, we will put into perspective the abovementioned discoveries to optimally modulate the spatiotemporal nature of complement activation and regulation at mucosal surfaces.
Collapse
Affiliation(s)
- Devesha H Kulkarni
- Division of Gastroenterology, Washington University School of Medicine, St. Louis, MO, USA
| | - Marick Starick
- Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Rafael Aponte Alburquerque
- Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Hrishikesh S Kulkarni
- Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO, USA.
| |
Collapse
|
3
|
Zhou X, Ganz AB, Rayner A, Cheng TY, Oba H, Rolnik B, Lancaster S, Lu X, Li Y, Johnson JS, Hoyd R, Spakowicz DJ, Slavich GM, Snyder MP. Dynamic Human Gut Microbiome and Immune Shifts During an Immersive Psychosocial Therapeutic Program. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.26.600881. [PMID: 38979211 PMCID: PMC11230355 DOI: 10.1101/2024.06.26.600881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Background Depression is a leading cause of disability worldwide yet its underlying factors, particularly microbial associations, are poorly understood. Methods We examined the longitudinal interplay between the microbiome and immune system in the context of depression during an immersive psychosocial intervention. 142 multi-omics samples were collected from 52 well-characterized participants before, during, and three months after a nine-day inquiry-based stress reduction program. Results We found that depression was associated with both an increased presence of putatively pathogenic bacteria and reduced microbial beta-diversity. Following the intervention, we observed reductions in neuroinflammatory cytokines and improvements in several mental health indicators. Interestingly, participants with a Prevotella-dominant microbiome showed milder symptoms when depressed, along with a more resilient microbiome and more favorable inflammatory cytokine profile, including reduced levels of CXCL-1. Conclusions Our findings reveal a protective link between the Prevotella-dominant microbiome and depression, associated with a less inflammatory environment and moderated symptoms. These insights, coupled with observed improvements in neuroinflammatory markers and mental health from the intervention, highlight potential avenues for microbiome-targeted therapies in depression management.
Collapse
Affiliation(s)
- Xin Zhou
- Department of Genetics, Stanford University School of Medicine, CA, USA
- Stanford Center for Genomics and Personalized Medicine, Stanford university School of Medicine, CA, USA
- These authors contributed equally to the work
| | - Ariel B. Ganz
- Department of Genetics, Stanford University School of Medicine, CA, USA
- Stanford Healthcare Innovation Lab, Stanford University, CA, USA
- These authors contributed equally to the work
| | - Andre Rayner
- Department of Genetics, Stanford University School of Medicine, CA, USA
| | - Tess Yan Cheng
- Department of Genetics, Stanford University School of Medicine, CA, USA
- Department of Microbiology, College of Arts and Sciences, University of Washington, WA, USA
| | - Haley Oba
- Department of Genetics, Stanford University School of Medicine, CA, USA
| | - Benjamin Rolnik
- Department of Genetics, Stanford University School of Medicine, CA, USA
- Stanford Healthcare Innovation Lab, Stanford University, CA, USA
| | - Samuel Lancaster
- Department of Genetics, Stanford University School of Medicine, CA, USA
| | - Xinrui Lu
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Sichuan, China
| | - Yizhou Li
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Sichuan, China
| | - Jethro S. Johnson
- Oxford Centre for Microbiome Studies, Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | - Rebecca Hoyd
- The Ohio State University Comprehensive Cancer Center, OH, USA
| | | | - George M. Slavich
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, USA
| | - Michael P. Snyder
- Department of Genetics, Stanford University School of Medicine, CA, USA
- Stanford Center for Genomics and Personalized Medicine, Stanford university School of Medicine, CA, USA
- Stanford Healthcare Innovation Lab, Stanford University, CA, USA
| |
Collapse
|
4
|
Sanchez-Garrido J, Baghshomali YN, Kaushal P, Kozik Z, Perry RW, Williams HRT, Choudhary J, Frankel G. Impaired neutrophil migration underpins host susceptibility to infectious colitis. Mucosal Immunol 2024:S1933-0219(24)00062-X. [PMID: 38936619 DOI: 10.1016/j.mucimm.2024.06.008] [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: 02/29/2024] [Revised: 06/07/2024] [Accepted: 06/19/2024] [Indexed: 06/29/2024]
Abstract
Citrobacter rodentium models infection with enteropathogenic Escherichia coli and ulcerative colitis (UC). While C57BL/6 (C57) mice recover, C3H/HeN (C3H) mice succumb to infection, partially due to increased colonic neutrophil elastase activity, also seen in UC patients; however, the underlying cause was unknown. Here, we found that bone marrow, blood, and colonic C57 neutrophils expressed (CD)11bHi and reached the infected colonic lumen, where they underwent productive NETosis. In contrast, while the number of C3H neutrophils increased in the bone marrow, blood, and colon, they remained CD11bLo and got trapped in the submucosa, away from C. rodentium, where they underwent harmful NETosis. CD11bLo neutrophils in C3H mice infected with CRi9, which triggers expression of neutrophil chemoattractants, reached the colonization site, resulting in host survival. UC patient neutrophils also displayed decreased levels of the activation/differentiation markers CD16/CXCR4. These results, suggesting that neutrophil malfunction contributes to exacerbated colitis, provide insight for future therapeutic prospects.
Collapse
Affiliation(s)
| | | | - Prashant Kaushal
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, United Kingdom
| | - Zuza Kozik
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, United Kingdom
| | - Robert W Perry
- Department of Metabolism, Digestion and Reproduction, Imperial College, London, United Kingdom
| | - Horace R T Williams
- Department of Metabolism, Digestion and Reproduction, Imperial College, London, United Kingdom
| | - Jyoti Choudhary
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, United Kingdom
| | - Gad Frankel
- Department of Life Sciences, Imperial College, London, United Kingdom
| |
Collapse
|
5
|
Carpenter S, O'Neill LAJ. From periphery to center stage: 50 years of advancements in innate immunity. Cell 2024; 187:2030-2051. [PMID: 38670064 PMCID: PMC11060700 DOI: 10.1016/j.cell.2024.03.036] [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: 12/20/2023] [Revised: 02/24/2024] [Accepted: 03/25/2024] [Indexed: 04/28/2024]
Abstract
Over the past 50 years in the field of immunology, something of a Copernican revolution has happened. For a long time, immunologists were mainly concerned with what is termed adaptive immunity, which involves the exquisitely specific activities of lymphocytes. But the other arm of immunity, so-called "innate immunity," had been neglected. To celebrate Cell's 50th anniversary, we have put together a review of the processes and components of innate immunity and trace the seminal contributions leading to the modern state of this field. Innate immunity has joined adaptive immunity in the center of interest for all those who study the body's defenses, as well as homeostasis and pathology. We are now entering the era where therapeutic targeting of innate immune receptors and downstream signals hold substantial promise for infectious and inflammatory diseases and cancer.
Collapse
Affiliation(s)
- Susan Carpenter
- University of California Santa Cruz, 1156 High St., Santa Cruz, CA 95064, USA.
| | - Luke A J O'Neill
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.
| |
Collapse
|
6
|
Jensen O, Trujillo E, Hanson L, Ost KS. Controlling Candida: immune regulation of commensal fungi in the gut. Infect Immun 2024:e0051623. [PMID: 38647290 DOI: 10.1128/iai.00516-23] [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] [Indexed: 04/25/2024] Open
Abstract
The intestinal microbiome harbors fungi that pose a significant risk to human health as opportunistic pathogens and drivers of inflammation. Inflammatory and autoimmune diseases are associated with dysbiotic fungal communities and the expansion of potentially pathogenic fungi. The gut is also the main reservoir for disseminated fungal infections. Immune interactions are critical for preventing commensal fungi from becoming pathogenic. Significant strides have been made in defining innate and adaptive immune pathways that regulate intestinal fungi, and these discoveries have coincided with advancements in our understanding of the fungal molecular pathways and effectors involved in both commensal colonization and pathogenesis within the gut. In this review, we will discuss immune interactions important for regulating commensal fungi, with a focus on how specific cell types and effectors interact with fungi to limit their colonization or pathogenic potential. This will include how innate and adaptive immune pathways target fungi and orchestrate antifungal immune responses, in addition to how secreted immune effectors, such as mucus and antimicrobial peptides, regulate fungal colonization and inhibit pathogenic potential. These immune interactions will be framed around our current understanding of the fungal effectors and pathways regulating colonization and pathogenesis within this niche. Finally, we highlight important unexplored mechanisms by which the immune system regulates commensal fungi in the gut.
Collapse
Affiliation(s)
- Owen Jensen
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Emma Trujillo
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Luke Hanson
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Kyla S Ost
- Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| |
Collapse
|
7
|
Jiang D, Soo N, Tan CY, Dankwa S, Wang HY, Theriot BS, Ardeshir A, Siddiqui NY, Van Rompay KKA, De Paris K, Permar SR, Goswami R, Surana NK. Commensal bacteria inhibit viral infections via a tryptophan metabolite. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.21.589969. [PMID: 38659737 PMCID: PMC11042330 DOI: 10.1101/2024.04.21.589969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
There is growing appreciation that commensal bacteria impact the outcome of viral infections, though the specific bacteria and their underlying mechanisms remain poorly understood. Studying a simian-human immunodeficiency virus (SHIV)-challenged cohort of pediatric nonhuman primates, we bioinformatically associated Lactobacillus gasseri and the bacterial family Lachnospiraceae with enhanced resistance to infection. We experimentally validated these findings by demonstrating two different Lachnospiraceae isolates, Clostridium immunis and Ruminococcus gnavus, inhibited HIV replication in vitro and ex vivo. Given the link between tryptophan catabolism and HIV disease severity, we found that an isogenic mutant of C. immunis that lacks the aromatic amino acid aminotransferase (ArAT) gene, which is key to metabolizing tryptophan into 3-indolelactic acid (ILA), no longer inhibits HIV infection. Intriguingly, we confirmed that a second commensal bacterium also inhibited HIV in an ArAT-dependent manner, thus establishing the generalizability of this finding. In addition, we found that purified ILA inhibited HIV infection by agonizing the aryl hydrocarbon receptor (AhR). Given that the AhR has been implicated in the control of multiple viral infections, we demonstrated that C. immunis also inhibited human cytomegalovirus (HCMV) infection in an ArAT-dependent manner. Importantly, metagenomic analysis of individuals at-risk for HIV revealed that those who ultimately acquired HIV had a lower fecal abundance of the bacterial ArAT gene compared to individuals who did not, which indicates our findings translate to humans. Taken together, our results provide mechanistic insights into how commensal bacteria decrease susceptibility to viral infections. Moreover, we have defined a microbiota-driven antiviral pathway that offers the potential for novel therapeutic strategies targeting a broad spectrum of viral pathogens.
Collapse
|
8
|
Kemper C. Complement: you gutsy thing! Trends Immunol 2024; 45:228-230. [PMID: 38538487 PMCID: PMC11015959 DOI: 10.1016/j.it.2024.03.003] [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: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 04/14/2024]
Abstract
Complement, traditionally perceived as a liver-derived and plasma-operative guardian against bloodborne pathogens, is increasingly recognized as a local and central player in tissue immunity. Two recent studies, by Xu et al. and Wu et al., validate this concept in the mouse gut, where extrahepatic, intestine-produced, and/or operative C3 protects against enteric infections.
Collapse
Affiliation(s)
- Claudia Kemper
- Complement and Inflammation Research Section, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD, USA.
| |
Collapse
|
9
|
Surprise find: a blood-based immune system is discovered in the gut. Nature 2024; 626:237. [PMID: 38317000 DOI: 10.1038/d41586-024-00245-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
|