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Bacteria have global regulatory systems that control several types of stress mechanisms. These include Pho regulon and the heat shock response, which are essential systems for environmental adaptation, such as nutrient limitation and proteotoxic stress. The Pho regulon and the heat shock response exemplify bacterial resilience, enabling rapid adaptation to fluctuating environmental conditions.Pho RegulonBacteria require phosphorus for essential cellular processes, including nucleic acid...
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The stress response system, also known as the fight-or-flight response, is the body's automatic physiological reaction to perceived threats. Hans Selye introduced the concept of General Adaptation Syndrome (GAS) to describe the predictable pattern of changes that occur in response to stress. GAS consists of three sequential stages: alarm, resistance, and exhaustion. This model helps explain how chronic stress can contribute to health problems.
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Psychoneuroimmunology (PNI) is a multidisciplinary field that examines how psychological factors, particularly stress, interact with the immune system and impact physical health. Research in PNI has shown that chronic or traumatic stress can disrupt both the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. These disruptions contribute to serious health conditions, including cardiovascular diseases.
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A Mouse Model for the Transition of Streptococcus pneumoniae from Colonizer to Pathogen upon Viral Co-Infection Recapitulates Age-Exacerbated Illness
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Host Stress Signals Stimulate Pneumococcal Transition from Colonization to Dissemination into the Lungs.

Fayez Alghofaili1,2, Hastyar Najmuldeen1,3, Banaz O Kareem1

  • 1Department of Respiratory Sciences, University of Leicestergrid.9918.9, Leicester, United Kingdom.

Mbio
|October 26, 2021
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Summary

Host stress hormones like norepinephrine (NE) enable Streptococcus pneumoniae to transition from harmless colonizer to dangerous pathogen. NE exposure increases bacterial translocation from the nasopharynx to the lungs, impacting cell size and capsule synthesis.

Keywords:
Streptococcus pneumoniaebacterial infectionstress hormonetwo-component regulatory systemvirulence

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Area of Science:

  • Microbiology
  • Pathogenesis
  • Host-Microbe Interactions

Background:

  • Streptococcus pneumoniae is a common nasopharyngeal colonizer and a significant human pathogen.
  • The transition of S. pneumoniae from commensal to pathogenic state is not fully understood.
  • Host stress hormones may play a role in this transition.

Purpose of the Study:

  • To investigate the role of catecholamine stress hormones in the transition of S. pneumoniae from commensal to pathogenic.
  • To identify the mechanisms and genetic factors involved in pneumococcal response to stress hormones.

Main Methods:

  • Exposure of S. pneumoniae to norepinephrine (NE), a stress hormone.
  • Analysis of metabolic profiles, cell associations, capsule synthesis, and cell size.
  • Systematic mutation of regulatory systems to identify genetic circuits involved in hormone response.

Main Results:

  • NE-exposed pneumococci showed increased translocation from nasopharynx to lungs in a mouse model.
  • NE treatment altered pneumococcal metabolic profiles, cell size, and capsule synthesis.
  • A unique genetic regulatory circuit, involving TCS09, was identified for stress hormone recognition and response.

Conclusions:

  • Catecholamine stress hormones are key signals triggering the pathogenic transition of S. pneumoniae.
  • Stress hormone exposure enhances pneumococcal lung colonization by altering cell characteristics and promoting migration.
  • The TCS09 protein is crucial for pneumococcal sensing and response to stress hormones, with clinical implications for critically ill patients.