LncRNA-Gm5532 deficiency alleviates bone resorption by inhibiting mitochondrial respiration through iASPP/NRF2

Area of Science:

• Molecular Biology
• Bone Biology
• Metabolism

Background:

• Osteoporosis involves excessive osteoclast activity and is linked to mitochondrial respiration.
• The role of long non-coding RNA Gm5532 in mitochondrial function during osteoclast differentiation is not well understood.
• Understanding Gm5532's regulatory mechanisms is crucial for developing osteoporosis therapies.

Purpose of the Study:

• To elucidate how Gm5532 regulates bone resorption via iron metabolism and mitochondrial respiration.
• To investigate the interaction between Gm5532, iASPP, and the NRF2 signaling pathway.
• To identify Gm5532 as a potential therapeutic target for osteoporosis.

Main Methods:

• Utilized Gm5532 knockout (KO) mouse models (aged, ovariectomized, iron-overloaded).
• Investigated the interaction between Gm5532 and RNA-binding protein iASPP.
• Analyzed the modulation of the KEAP1/NRF2 axis and its downstream targets (Ftl, Fth, Fpn1).
• Assessed intracellular labile iron levels, mitochondrial biogenesis, and respiration.

Main Results:

• Gm5532 KO alleviated bone loss by reducing osteoclast formation and activity.
• Gm5532 directly interacts with iASPP, destabilizing NRF2.
• Gm5532 KO enhanced iASPP-KEAP1 binding, stabilizing NRF2 and upregulating iron metabolism genes.
• Reduced intracellular iron suppressed mitochondrial function and osteoclast differentiation.

Conclusions:

• Gm5532 is a critical regulator of bone resorption by modulating iron homeostasis and mitochondrial respiration.
• A novel Gm5532-iASPP-NRF2 signaling axis links iron metabolism to mitochondrial respiration and osteoclast function.
• This pathway presents a promising therapeutic target for osteoporosis.