Recovery of murine mast cell dysfunction induced by simulated microgravity

초록

The cross-linking of high-affinity IgE receptors (FcεRI) on mast cell surfaces triggers the rapid release of proinflammatory molecules, such as histamine, from cytoplasmic granules, along with late-phase cytokine production, both of which are crucial in the pathogenesis of allergic diseases. Microgravity is known to alter astronauts' immune systems during spaceflight, but its effects on IgE-FcεRI-mediated mast cell function remain poorly understood. To address this, murine bone marrow-derived mast cells (BMMCs) were cultured in a rotary cell culture system (RCCS) that simulates a microgravity (SMG) environment. After three days of SMG exposure, BMMCs displayed significantly reduced secretion of β-hexosaminidase, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) upon FcεRI activation compared to cells cultured under normal gravity (1G). Impaired secretion observed in the SMG condition was fully restored following a four-day incubation under 1G condition. These findings highlight the impact of microgravity on mast cell function and its subsequent recovery in normal gravity, providing valuable insights into immune system dysfunction during spaceflight and contributing to the development of future space medicine strategies.