A new study shows that hematopoietic stem cells respond urgently to Salmonella infection in the first few hours after infection, receiving support from bone marrow mesenchymal stem cells.
Scientists from the University of East Anglia (UEA) hope that the results, published on November 14, 2019 in the PNAS journal, will help develop new approaches to treating people infected with Salmonella and other bacterial diseases.
Lead researcher Dr. Stuart Rushworth of the Norwich Medical School at UEA said: “Salmonella is one of the most common causes of food poisoning in the world. Symptoms include diarrhea, vomiting, abdominal pain, and fever”.
“Most people recover without treatment but young children, the elderly and people who have immune systems that are not working properly have a greater risk of becoming severely ill and it can be deadly”.
“We wanted to find out how the immune system responds to Salmonella bacterial infection. Knowing more about how our bodies respond could help develop new ways to treat people with weak immune systems, such as the elderly”.
The UEA team collaborated with Norwich Research Park colleagues at the Norfolk and Norwich University Hospital (NNUH), the Quadram Institute and the Earlham Institute (EI), to study mitochondria— tiny intracellular organelles that provide cells with energy.
Scientists analyzed the immune response to bacterial Salmonella infection by using blood and bone marrow cells donated for research by NNUH patients. The researchers also collaborated with experts on salmonellosis from the Quadram Institute, using special microscopes and DNA analysis to find out how mitochondria move between different types of cells.
They found that in the bone marrow, where blood cells supporting hematopoiesis are produced, stromal mesenchymal stem cells were forced to transfer their energy generating by mitochondria to neighboring blood stem cells.
Dr. Rushworth said: “We found that these support cells were effectively ‘charging’ the stem cells and enabling them to make millions more bacteria-fighting white blood cells. It was not previously known how blood stem cells acquire the energy they need to mount an immune response to infection. Mitochondria are like tiny batteries which power cells. In response to infection, the immune system takes mitochondria from surrounding support cells to power up the immune response.”
In addition to determining how and why mitochondria are transmitted, the study discusses the potential impact on the treatment of infections in the future.
“Our results provide insight into how the blood and immune system is able to respond so quickly to infection”, – said Dr. Rushworth. “Working out the mechanism through which this ‘power boost’ works gives us new ideas on how to strengthen the body’s fight against infection in the future. This work could help inform how older people with infection might be treated. It is an essential first step towards exploiting this biological function therapeutically in the future.”
Director of Science at EI Prof Federica Di Palma, said: “This collaboration demonstrates how interdisciplinary research approaches are key to meeting the health needs of the future. The integrated efforts of three institutions with different scientific expertise has allowed us to understand important mechanisms used by our cells to fight bacterial infections, providing valuable insight into future therapeutic applications.”