RNA thermosensors facilitate Streptococcus pneumoniae and Haemophilus influenzae immune evasion

• Published in: PLoS pathogens 2021-04, Vol.17 (4), p.e1009513-e1009513
• Main Authors: Eichner, Hannes, Karlsson, Jens, Spelmink, Laura, Pathak, Anuj, Sham, Lok-To, Henriques-Normark, Birgitta, Loh, Edmund
• Format: Article
• Language: English
• Subjects: Bacteria; Bacterial Capsules - metabolism; Base Sequence - genetics; Binding sites; Biology and Life Sciences; Biosensors; Capsular polysaccharides; Complement Factor H - metabolism; Complement system; Environment; Gene expression; Genetic aspects; Haemophilus Infections - microbiology; Haemophilus influenzae - genetics; Haemophilus influenzae - immunology; Haemophilus influenzae - physiology; Health aspects; Hemophilus influenzae; Host-parasite relationships; Immune evasion; Immune response; Macrophages; Mathematical analysis; Medicin och hälsovetenskap; Medicine and Health Sciences; Meningitis; Meningitis, Bacterial - microbiology; Nasopharynx - microbiology; Operons; Opsonophagocytosis; Pathogens; Phagocytosis; Pneumococcal Infections - genetics; Pneumococcal Infections - microbiology; Polysaccharides; Polysaccharides, Bacterial - metabolism; Proteins; Saccharides; Statistics; Streptococcus infections; Streptococcus pneumoniae; Streptococcus pneumoniae - immunology; Streptococcus pneumoniae - physiology; Survival; Temperature; Temperature effects; Thermosensing; Vaccines; Virulence; Virulence (Microbiology); Virulence factors; Virulence Factors - metabolism
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1009513

Bacterial meningitis is a major cause of death and disability in children worldwide. Two human restricted respiratory pathogens, Streptococcus pneumoniae and Haemophilus influenzae, are the major causative agents of bacterial meningitis, attributing to 200,000 deaths annually. These pathogens are often part of the nasopharyngeal microflora of healthy carriers. However, what factors elicit them to disseminate and cause invasive diseases, remain unknown. Elevated temperature and fever are hallmarks of inflammation triggered by infections and can act as warning signals to pathogens. Here, we investigate whether these respiratory pathogens can sense environmental temperature to evade host complement-mediated killing. We show that productions of two vital virulence factors and vaccine components, the polysaccharide capsules and factor H binding proteins, are temperature dependent, thus influencing serum/opsonophagocytic killing of the bacteria. We identify and characterise four novel RNA thermosensors in S. pneumoniae and H. influenzae, responsible for capsular biosynthesis and production of factor H binding proteins. Our data suggest that these bacteria might have independently co-evolved thermosensing abilities with different RNA sequences but distinct secondary structures to evade the immune system.