What can you do to keep your bones healthy and strong? In addition to sporting the ever-trendy milk mustache, you might want to avoid mutations in miR-2861, a newly discovered miRNA involved in osteoblast differentiation. A team of Chinese researchers identified miR-2861 by cloning miRNAs from primary mouse osteoblasts (the cells responsible for bone formation).
The team went on to show that miR-2861, which is expressed primarily in osteoblasts, promotes osteoblast differentiation by targeting the histone deacetylase 5 (HDAC5) transcript. HDAC5 inhibits bone differentiation by deacetylating lysine residues in the transcription factor Runx2, which enhances its degradation. During osteogenesis, miR-2861 inhibits HDAC5 protein expression, and as a result, levels of the differentiation-inducing Runx2 increase.
To ensure that the physiological relevance of miR-2861 isn’t a bone of contention, the researchers scoped out the miRNA expression in bone samples from patients with primary osteoporosis and bumped into two key findings:
- Two adolescent osteoporosis patients, a brother and sister, were found to lack detectable miR-2861 expression because of a homozygous pre-miR-2861 mutation thought to affect its processing.
- The C-to-G mutation wasn’t found in healthy people or in other patients with osteoporosis, suggesting that the mutation is a rare variant that contributes to primary osteoporosis.
Bone up on all the details at Journal of Clinical Investigation, November 2009.