A stress enzyme in bone stem cells links diabetes and alcohol to mitochondrial failure and bone loss — in lab models
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Osteoporosis and osteonecrosis are familiar skeletal complications of type 2 diabetes and chronic alcohol consumption, but the cellular link between metabolic stress and failing bone has been unclear. A team at the Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences (Gao, Yuan, Huang and colleagues, corresponding author Min Guan), publishing in Nature Communications on October 20, 2026, identifies acetyl-CoA synthetase 1 (ACSS1) as a stress responder that mediates communication between the mitochondria and the nucleus in bone marrow skeletal stem cells.
How does nutrient stress switch ACSS1 on?
Nutrient excess from glucose, alcohol or acetate upregulated ACSS1 through a mitochondrial reactive-oxygen-species activated integrated stress response involving the transcription factor CEBPB. The accumulated ACSS1 then forced excessive acetyl-CoA production from acetate — whether supplied directly or generated from glucose and ethanol — driving widespread mitochondrial protein hyperacetylation.
What does the hyperacetylation break?
One target mattered most: the enzyme ME2 was specifically inactivated by acetylation at lysine 94. Because ME2 supports the malate-aspartate shuttle, its loss disturbed redox balance and created a self-perpetuating cycle of oxidative stress that deepened mitochondrial dysfunction and impaired osteogenesis — the stem cells' ability to build bone.
Can the cycle be reversed — and what are the limits?
In male mouse models of type 2 diabetes and chronic alcohol consumption, genetically deleting Acss1 from osteoprogenitor cells, or delivering a non-acetylatable ME2 variant (ME2K94R) by AAV, restored mitochondrial resilience, osteogenic capacity and bone formation, protecting against osteoporosis and osteonecrosis. The limits are firm: this is mouse and cell work, in male animals, with a patent application pending on the AAV approach (declared by the authors). No human data exist, and ACSS1 is a candidate target, not a treatment.
Where the evidence stands
- Established: Type 2 diabetes and chronic alcohol use damage bone, and mitochondrial dysfunction in skeletal stem cells impairs bone formation.
- Preliminary: In mouse models and stem cells (Nature Communications, Oct 20, 2026), nutrient stress raised ACSS1 via a mitochondrial ROS stress pathway; ACSS1-driven hyperacetylation inactivated ME2 (lysine 94), and deleting Acss1 or expressing non-acetylatable ME2 restored mitochondrial function and bone formation in diabetic and alcohol-exposed male mice.
- Absent: Human evidence for the ACSS1–ME2 pathway in bone disease, and any therapy targeting it in people.
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