Blocking STING helps preserve bone in ageing mice

Lifespan.io · Article

Researchers found that the cGAS-STING immune pathway becomes progressively more active in bone marrow macrophages as mice age, driven in part by DPP4 secreted from senescent marrow fat cells together with leaked mitochondrial DNA. Activated STING raised CD38, which degrades NAD+ and its precursor NMN, leaving neighbouring bone-forming stem cells with impaired mitochondria and less capacity to build bone. Silencing Sting in macrophages from 12 to 18 months of age preserved bone density and structure, and a drug combination - STING inhibitor H-151 plus NMN - preserved bone to a degree largely similar to the established osteoporosis drug alendronate in the same experiment.

Key takeaways:

• Bone ageing here is an immune-environment story, not just wear: marrow fat, macrophage inflammation and NAD+ depletion connect into one chain that weakens bone formation
• The effect flips with age: young mice lacking STING showed reduced bone density, while older mice lacking it were protected against bone loss - timing matters for any future intervention
• The intervention combined two treatments at once, so the study cannot separate the effect of STING inhibition from the effect of NMN supplementation, and the study was small

Hype check: Proven - a STING-driven mechanism and bone preservation in ageing mice, in lab and animal work only. Promising - STING as a drug target for skeletal ageing. Marketing - any framing of this as an osteoporosis treatment for people; no human has been treated in this work.