The P2X(7) receptor and intracellular pathogens: a continuing struggle
Robson Coutinho-Silva1, Gladys Corrêa, Ali Abdul Sater
1Immunobiology Program, Biophysics Institute Carlos Chagas Filho, Federal University of Rio de Janeiro, 21941-902, RJ, Brazil, rcsilva@biof.ufrj.br.
Purinergic Signalling
|February 14, 2009
Summary
The P2X(7) receptor is crucial for innate immunity, fighting microbial infections by activating inflammasomes and directly killing pathogens. Genetic variations in P2X(7) influence human susceptibility to infections.
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- The purinergic receptor P2X(7) plays a key role in the innate immune response.
- It is involved in host defense against microbial infections.
Purpose of the Study:
- To review the role of P2X(7) in controlling intracellular pathogen infections.
- To discuss microbial factors that inhibit P2X(7) activity.
- To explore the link between P2X(7) gene polymorphisms and infection susceptibility.
Main Methods:
- Literature review of studies on P2X(7) and microbial infections.
- Analysis of P2X(7) signaling pathways, including inflammasome activation.
- Examination of host-pathogen interactions involving P2X(7).
Main Results:
- P2X(7) activation by ATP triggers inflammasome activation and cytokine release.
- P2X(7) can directly eliminate intracellular pathogens within macrophages and epithelial cells.
- Some pathogens have evolved virulence factors to counteract P2X(7) function.
Conclusions:
- P2X(7) is a critical host defense mechanism against intracellular pathogens.
- Understanding P2X(7) function and its manipulation by microbes is vital for developing new anti-infective strategies.
- Human P2X(7) polymorphisms are associated with varying susceptibility to infections.
Related Concept Videos
01:31Defense Against Bacterial Pathogens
The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
01:25Colonisation of Pathogens
Pathogen colonization of host tissues is a critical step in the development of infectious diseases. Various pathogenic microorganisms, including bacteria, fungi, viruses, and protozoa, have evolved complex strategies to attach to, invade, and persist within host environments. These mechanisms enable pathogens to establish infections, evade immune responses, and resist antimicrobial treatments.Attachment to Host CellsIn bacteria, colonization typically begins with adherence to host epithelial...
01:28Regulation of Bacterial Virulence
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
01:26Gastritis II: Pathophysiology
The pathophysiology of gastritis begins with the colonization of the stomach lining by Helicobacter pylori (H. pylori). This bacterium spreads mainly via the oral-oral route through saliva or shared utensils, and can also be transmitted in overcrowded or unhygienic environments through contaminated water, despite its brief survival outside the body.ColonizationOnce ingested, H. pylori enters the stomach and begins colonization by navigating through the mucus layer lining the stomach wall. It...
01:09GPCRs Regulate Adenylyl Cylase Activity
Some GPCRs transmit signals through adenylyl cyclase (AC), a transmembrane enzyme. AC helps synthesize second messenger cyclic adenosine monophosphate (cAMP). AC catalyzes cyclization reaction and converts ATP to cAMP by releasing a pyrophosphate. The pyrophosphate is further hydrolyzed to phosphate by the enzyme pyrophosphatase, which drives cAMP synthesis to completion. However, cAMP is rapidly degraded to 5′ AMP by the enzymes phosphodiesterase (PDE), preventing overstimulation of cells.
Two...
Two...
01:20Determinants of Bacterial Pathogenicity and Virulence
Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...