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Heggi MT, Nour El-Din HT, Morsy DI, Abdelaziz NI, Attia AS. Microbial evasion of the complement system: a continuous and evolving story. Front Immunol 2024; 14:1281096. [PMID: 38239357 PMCID: PMC10794618 DOI: 10.3389/fimmu.2023.1281096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/30/2023] [Indexed: 01/22/2024] Open
Abstract
The complement system is a fundamental part of the innate immune system that plays a key role in the battle of the human body against invading pathogens. Through its three pathways, represented by the classical, alternative, and lectin pathways, the complement system forms a tightly regulated network of soluble proteins, membrane-expressed receptors, and regulators with versatile protective and killing mechanisms. However, ingenious pathogens have developed strategies over the years to protect themselves from this complex part of the immune system. This review briefly discusses the sequence of the complement activation pathways. Then, we present a comprehensive updated overview of how the major four pathogenic groups, namely, bacteria, viruses, fungi, and parasites, control, modulate, and block the complement attacks at different steps of the complement cascade. We shed more light on the ability of those pathogens to deploy more than one mechanism to tackle the complement system in their path to establish infection within the human host.
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Affiliation(s)
- Mariam T. Heggi
- Clinical Pharmacy Undergraduate Program, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Hanzada T. Nour El-Din
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | | | | | - Ahmed S. Attia
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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Nock AM, Aistleitner K, Clark TR, Sturdevant D, Ricklefs S, Virtaneva K, Zhang Y, Gulzar N, Redekar N, Roy A, Hackstadt T. Identification of an autotransporter peptidase of Rickettsia rickettsii responsible for maturation of surface exposed autotransporters. PLoS Pathog 2023; 19:e1011527. [PMID: 37523399 PMCID: PMC10414592 DOI: 10.1371/journal.ppat.1011527] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/10/2023] [Accepted: 07/02/2023] [Indexed: 08/02/2023] Open
Abstract
Members of the spotted fever group rickettsia express four large, surface-exposed autotransporters, at least one of which is a known virulence determinant. Autotransporter translocation to the bacterial outer surface, also known as type V secretion, involves formation of a β-barrel autotransporter domain in the periplasm that inserts into the outer membrane to form a pore through which the N-terminal passenger domain is passed and exposed on the outer surface. Two major surface antigens of Rickettsia rickettsii, are known to be surface exposed and the passenger domain cleaved from the autotransporter domain. A highly passaged strain of R. rickettsii, Iowa, fails to cleave these autotransporters and is avirulent. We have identified a putative peptidase, truncated in the Iowa strain, that when reconstituted into Iowa restores appropriate processing of the autotransporters as well as restoring a modest degree of virulence.
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Affiliation(s)
- Adam M. Nock
- Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Karin Aistleitner
- Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Tina R. Clark
- Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Dan Sturdevant
- Genomics Research Section, Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Stacy Ricklefs
- Genomics Research Section, Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Kimmo Virtaneva
- Genomics Research Section, Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Yixiang Zhang
- Protein Chemistry Unit, Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Naila Gulzar
- Integrated Data Sciences Section, Research Technologies Branch, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Neelam Redekar
- Integrated Data Sciences Section, Research Technologies Branch, NIAID, NIH, Bethesda, Maryland, United States of America
| | - Amitiva Roy
- Bioinformatics and Computational Biology Branch, Office of Cyber Infrastructure and Computational Biology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
| | - Ted Hackstadt
- Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, NIAID, NIH; Hamilton, Montana, United States of America
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Moonlighting in Rickettsiales: Expanding Virulence Landscape. Trop Med Infect Dis 2022; 7:tropicalmed7020032. [PMID: 35202227 PMCID: PMC8877226 DOI: 10.3390/tropicalmed7020032] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/05/2022] [Accepted: 02/17/2022] [Indexed: 12/22/2022] Open
Abstract
The order Rickettsiales includes species that cause a range of human diseases such as human granulocytic anaplasmosis (Anaplasma phagocytophilum), human monocytic ehrlichiosis (Ehrlichia chaffeensis), scrub typhus (Orientia tsutsugamushi), epidemic typhus (Rickettsia prowazekii), murine typhus (R. typhi), Mediterranean spotted fever (R. conorii), or Rocky Mountain spotted fever (R. rickettsii). These diseases are gaining a new momentum given their resurgence patterns and geographical expansion due to the overall rise in temperature and other human-induced pressure, thereby remaining a major public health concern. As obligate intracellular bacteria, Rickettsiales are characterized by their small genome sizes due to reductive evolution. Many pathogens employ moonlighting/multitasking proteins as virulence factors to interfere with multiple cellular processes, in different compartments, at different times during infection, augmenting their virulence. The utilization of this multitasking phenomenon by Rickettsiales as a strategy to maximize the use of their reduced protein repertoire is an emerging theme. Here, we provide an overview of the role of various moonlighting proteins in the pathogenicity of these species. Despite the challenges that lie ahead to determine the multiple potential faces of every single protein in Rickettsiales, the available examples anticipate this multifunctionality as an essential and intrinsic feature of these obligates and should be integrated into available moonlighting repositories.
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