Akihiro Shimba

Animals have evolved circadian rhythms to adapt to the 24-h day-night cycle. Circadian rhythms are controlled by molecular clocks in the brain and periphery, which is driven by clock genes. The circadian rhythm is propagated from the brain to the periphery by nerves and hormones. Glucocorticoids (GCs) are a class of steroid hormones produced by the adrenal cortex under the control of the circadian rhythm and the stress. GCs have both positive and negative effects on the immune system. Indeed, th

Glucocorticoids (GCs) are a class of steroid hormones secreted from the adrenal cortex. Their production is controlled by circadian rhythm and stress, the latter of which includes physical restraint, hunger, and inflammation. Importantly, GCs have various effects on immunity, metabolism, and cognition, including pleiotropic effects on the immune system. In general, GCs have strong anti-inflammatory and immunosuppressive effects. Indeed, they suppress inflammatory cytokine expression and cell-med

Environmental cues such as the day-night cycle or stressors trigger the production of glucocorticoids (GCs) by the adrenal cortex. GCs are well known for their anti-inflammatory effects that suppress the production of inflammatory cytokines and induce the apoptosis of lymphocytes. Recent studies in mice, however, have revealed pro-inflammatory effects. The diurnal oscillation of GCs induces the expression of IL-7 receptor α (IL-7Rα) and C-X-C motif chemokine receptor 4 (CXCR4) at the active phas

Stress can trigger acute inflammation by increasing the pro-inflammatory cytokine interleukin (IL)-17 for injury and infection, while inducing the production of the immunosuppressive hormone glucocorticoids (GCs). However, the mechanism through which stress-induced GCs enhance acute inflammation by directly regulating the development of IL-17-producing helper T (Th17) cells remains unclear. Here, we demonstrate that GCs promote Th17 cell differentiation and survival in both mice and humans. Stre

IL-7 and IL-2 are evolutionarily related cytokines that play critical roles in the development and expansion of immune cells. Although both IL-7R and IL-2R activate similar signaling molecules, whether their signals have specific or overlapping functions during lymphocyte differentiation remains unclear. To address this question, we generated IL-7R α-chain (IL-7Rα)/IL-2R β-chain (IL-24β) (72R) knock-in mice expressing a chimeric receptor consisting of the extracellular domain of IL-7Rα and the i

Abstract The immune system is deeply affected by steroid hormones. Glucocorticoids are a group of steroid hormones with strong immunosuppressive effects and widely used in clinical practice. However, whether glucocorticoids physiologically control homeostasis and response of the immune system remains unclear. We found that glucocorticoid receptor up-regulates IL-7 receptor (IL-7R) of T cells by binding to an enhancer of the IL-7R locus, and the induction followed circadian rhythm consistent with