Mechanisms of pyroptosis in modulating osteoblast function under simulated microgravity.

Area of Science:

• Biomedical research
• Space medicine
• Cell biology

Background:

• Mechanical unloading in microgravity causes bone loss, hindering space exploration.
• The precise mechanisms behind microgravity-induced bone loss are not fully understood.

Purpose of the Study:

• To investigate the role of pyroptosis in osteoblasts under simulated microgravity.
• To determine how pyroptosis affects osteoblast functionality and bone health.

Main Methods:

• Simulated microgravity was established using a rotary cell culture system.
• Osteoblast proliferation, necrosis, differentiation, and mineralization were assessed.
• Pyroptosis was detected using fluorescence staining and electron microscopy, with caspase-1 activity measured.
• Gene and protein expression of key pyroptosis and bone markers were analyzed via qPCR, Western blot, and ELISA.

Main Results:

• Simulated microgravity induced pyroptosis in osteoblasts, evidenced by increased PI fluorescence and membrane pore formation.
• Osteoblast proliferation decreased, while necrosis and LDH release increased under simulated microgravity.
• Pyroptosis markers (NLRP3, caspase-1, GSDMD, IL-1β, IL-18) were upregulated, and caspase-1 activity increased.
• Inhibition of pyroptosis enhanced osteoblast differentiation markers (OCN, COL-I).

Conclusions:

• Pyroptosis is activated in osteoblasts under simulated microgravity, negatively impacting their osteogenic differentiation function.
• Pyroptosis represents a potential mechanism contributing to microgravity-induced bone loss.
• Modulating pyroptosis offers a novel therapeutic avenue for bone damage and repair in extreme mechanical environments.