Optogenetic-Induced Muscle Loading Leads to Mechanical Adaptation of the Achilles Tendon Enthesis in Mice.
Elahe GanjiSyeda N LamiaMatthew StepanovichNoelle WhyteRobert W GouletAdam C AbrahamMegan L KillianPublished in: bioRxiv : the preprint server for biology (2023)
Skeletal shape depends on transmission of contractile muscle forces from tendon to bone across the enthesis. Loss of muscle loading impairs enthesis development, yet little is known if and how the postnatal enthesis adapts to increased loading. Here, we studied adaptations in enthesis structure and function in response to increased loading using optogenetically-induced muscle contraction in young (i.e., growth) and adult (i.e., mature) mice. Daily bouts of unilateral optogenetic loading in young mice led to radial calcaneal expansion and warping. This also led to a weaker enthesis with increased collagen damage, with little change in adult mice. We then used RNA-sequencing to identify pathways associated with increased mechanical loading during growth. In tendon, we found enrichment of glycolysis, focal adhesion, and cell-matrix interactions. In bone, we found enrichment of inflammation and cell cycle. Together, we demonstrate the utility of optogenetic-induced muscle contraction to elicit in vivo adaptation of the enthesis.
Keyphrases
- skeletal muscle
- cell cycle
- high fat diet induced
- high glucose
- diabetic rats
- oxidative stress
- single cell
- smooth muscle
- cell proliferation
- drug induced
- bone mineral density
- insulin resistance
- physical activity
- escherichia coli
- young adults
- soft tissue
- staphylococcus aureus
- biofilm formation
- childhood cancer
- high intensity
- ultrasound guided