B cells maintain stockpiles of calcium ions (Ca2+), which are released during the course of the immune response. When the presence of a foreign antigen stimulates the B cell receptor (BCR) complex, these internal reserves of Ca2+ get released into the cell, subsequently triggering the opening of channels in the cell membrane that allow the entry of even more Ca2+.
Immunologists generally considered these ions as essential currency for many key cellular processes. “Ca2+ signaling in B cells is widely assumed to be responsible for functions including B cell development, immune response and antibody production,” says Yoshihiro Baba of the Immunology Frontier Research in Osaka University and formerly with the RIKEN Research Center for Allergy and Immunology in Yokohama. However, the direct effects of this bulk Ca2+ entry, also known as store-operated Ca2+ (SOC) influx, are poorly understood.
To examine the importance of this mechanism, Baba and colleagues genetically engineered mice whose B cells lack the genes encoding STIM1 or STIM2, two proteins involved with SOC influx1. Their results suggest that this pathway plays a far more narrowly defined role than was previously expected.
The researchers determined that these two proteins cooperatively contribute to the management of Ca2+ influx, and facilitate B cell proliferation following BCR-mediated signaling. However, they appear to have no role in the actual immune response, as mice with STIM1- and STIM2-deficient B cells were still capable of mounting an antibody response against foreign antigens.
On the other hand, both factors proved important for the function of regulatory B cells, which produce anti-inflammatory factors such as interleukin-10 (IL-10) and help prevent the immune system from over-reacting or attacking host tissues. Without these STIM proteins, mouse B cells produced only minimal amounts of IL-10. Baba and colleagues determined that the absence of STIM1 and STIM2 greatly exacerbates the incidence and severity of inflammatory pathology in a mouse model of multiple sclerosis. Since the action of IL-10 suppresses a variety of autoimmune conditions, these findings may indicate a general mechanism that could be targeted for the treatment of such disorders. “Our study suggests that a failure to balance Ca2+ levels may lead to autoimmune disease. This is a very exciting finding,” says Baba.
He and his colleagues are now keen to better understand the Ca2+-dependent anti-inflammatory B cells. “We are trying to show when and where regulatory B cells function, and what cells are targeted by them,” he says, “and to understand what type of inflammation—chronic or acute—is sensitive to IL-10-producing B cells.”
The corresponding author for this highlight is based at the Laboratory for Lymphocyte Differentiation, RIKEN Research Center for Allergy and Immunology
Repairing damaged hearts with self-healing heart cells
22.08.2017 | National University Health System
Biochemical 'fingerprints' reveal diabetes progression
22.08.2017 | Umea University
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences