Scientists have recognized the immune-boosting capabilities of vitamin A for the better part of a century, even without fully understanding how it helps the body fight off bacteria and viruses.
“Soon after its discovery, vitamin A was termed ‘the anti-infective vitamin’ and was widely used to enhance recovery; but with the introduction of antibiotics, the therapeutic use of vitamin A diminished,” says Sidonia Fagarasan of the RIKEN Center for Allergy and Immunology in Yokohama.
Fagarasan and her colleagues have now revealed how vitamin A deficiency can critically undermine the body’s initial defense against infection. B1 cells within the peritoneal cavity (PEC), the space surrounding the intestines and other organs, are important ‘first responders’ to the presence of pathogens (Fig. 1). Upon activation, B1 cells mature into cells that produce immunoglobulin M (IgM) and A (IgA) antibodies that target bacteria and viruses in the bloodstream and gut, respectively. “These cells usually act at the early time window after infection, thus preventing the expansion of microorganisms,” explains Fagarasan.
Mikako Maruya, a young researcher with her team, observed dramatic depletion of PEC B1 cells in mice fed a vitamin A-free diet, which grew more severe with age. Accordingly, these vitamin A-deficient (VAD) animals also produced lower levels of both IgA and IgM, and failed to marshal an effective antibody response following injection with pneumonia vaccine. B1 cells transplanted from healthy donors to VAD animals showed impaired proliferation, and considerably dwindled in number over the course of a week. Importantly, bone marrow-derived stem cells from VAD mice retained the capacity to give rise to B1 cells, although they failed to do so in the absence of vitamin A.
The key turned out to be nuclear factor of activated T cells 1 (NFATc1), a transcription factor protein that regulates expression of numerous important genes in B1 cells. The researchers observed reduced NFATc1 levels in VAD B1 cells, but found that expression could be largely restored if these mice were injected with ATRA, a product of cellular vitamin A metabolism. This also led to rapid B1 cell proliferation, which increased in number by more than four-fold increase within 10 days of injection.
Motivated by these findings, Fagarasan is now exploring how levels of vitamin A affect other components of the immune response to infection. “We were very excited to discover something that we had never thought about, that active products of vitamin A contribute to the induction of some very important transcription factors,” she says.
The corresponding author for this highlight is based at the Laboratory for Mucosal Immunity, RIKEN Center for Allergy and Immunology
 Maruya, M., Suzuki, K., Fujimoto, H., Miyajima, M., Kanagawa, O., Wakayama, T. & Fagarasan, S. Vitamin A-dependent transcriptional activation of the nuclear factor of activated T cells c1 (NFATc1) is critical for the development and survival of B1 cells. Proceedings of the National Academy of Sciences USA 108, 722–727 (2011).
gro-pr | Research asia research news
Fine organic particles in the atmosphere are more often solid glass beads than liquid oil droplets
21.04.2017 | Max-Planck-Institut für Chemie
Study overturns seminal research about the developing nervous system
21.04.2017 | University of California - Los Angeles Health Sciences
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...
Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.
A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
21.04.2017 | Physics and Astronomy
21.04.2017 | Health and Medicine
21.04.2017 | Physics and Astronomy