Introduction:
Researchers from the University of British Columbia (UBC) and BC Children's Hospital have conducted a study revealing that sugar sialic acid, a component of the protective intestinal mucus layer, acts as a fuel for disease-causing bacteria in the gut. The findings, published in the Proceedings of the National Academy of Sciences (PNAS), have significant implications for the treatment of intestinal bacterial infections and various chronic diseases associated with gut bacteria, including inflammatory bowel disease (IBD), celiac disease, irritable bowel syndrome, and short bowel syndrome.
Understanding the Role of Sugar in Bacterial Infections:
Dr. Bruce Vallance, a professor in the department of pediatrics at UBC and investigator at BC Children's Hospital, explains that bacteria must first establish themselves in the intestines, overcome the body's defense mechanisms, and then proliferate. By targeting the sugar sialic acid or the mechanisms by which pathogens detect it, potential treatments could be developed to prevent clinically important diseases caused by these bacteria.
Implications for Children and Rising Inflammatory Diseases:
Inflammatory diseases, such as IBD, are increasingly prevalent in children, who are more susceptible to gut bacterial infections due to their immature immune systems. Dr. Vallance and his team, including lead author and UBC graduate student Qiaochu Liang, along with UBC research associate Dr. Hongbing Yu, sought to uncover the factors that enable bacterial pathogens to survive and multiply within the intestines.
The Role of Sialic Acid Consumption:
The researchers focused on Citrobacter rodentium, an intestinal bacterial pathogen in mice that serves as a model for human E. coli infections. They discovered that these bacteria possess genes responsible for sialic acid consumption, and when these genes were removed, the growth of the bacteria was hindered.
The Role of Virulence Proteins:
Upon consuming sugars, the bacteria produced two specific virulence proteins that facilitated their penetration of the colonic mucus layer and adherence to the underlying epithelial cells. This finding sheds light on how bacteria can evolve over time, exacerbating the disease they cause.
Targeting Sugars to Combat Bacterial Infections:
Dr. Vallance suggests that specific nutrients such as sialic acid and other sugars could be targeted to eliminate dangerous bacteria from the intestine. Ongoing research is investigating the involvement of other sugars in promoting the growth of pathogenic bacteria. Additionally, the team is searching for resident beneficial bacteria (probiotics) that can outcompete harmful bacteria by consuming the sugars, thereby limiting their availability.
Exploring Interactions Between Resident and Pathogenic Bacteria:
The researchers plan to explore the interactions between resident and pathogenic bacteria further. Pathogenic bacteria cannot access sugars on their own and require assistance from normally harmless resident bacteria. These accomplice bacteria either provide the sugars directly to the dangerous bacteria or the dangerous bacteria find a way to steal them. Understanding these interactions could lead to innovative strategies to block pathogenic bacteria and address the urgent need for alternative approaches in the face of increasing antibiotic resistance.
Conclusion:
This study funded by the Canadian Institutes of Health Research and Crohn's and Colitis Canada has revealed the significance of sugar sialic acid in fueling disease-causing bacteria in the gut. The findings provide valuable insights into the development of treatments for intestinal bacterial infections and associated chronic diseases. By targeting sugars or disrupting their availability, researchers aim to inhibit the growth and survival of harmful bacteria, offering new possibilities for combating bacterial infections when antibiotic resistance is a growing concern.
