Bone-fat linkage via interleukin-11 in response to mechanical loading

Area of Science:

• Bone Biology
• Metabolic Regulation
• Endocrinology

Background:

• Bone formation is regulated by factors like mechanical loading and parathyroid hormone (PTH), which stimulate Interleukin-11 (IL-11) gene transcription.
• Aging and glucocorticoid excess suppress IL-11, highlighting its role in bone health.
• IL-11 influences bone metabolism by modulating Wnt signaling.

Purpose of the Study:

• To elucidate the signaling pathways involved in IL-11 gene transcription.
• To investigate the role of IL-11 in mediating the effects of mechanical loading on bone.
• To explore the connection between exercise, bone metabolism, and energy supply from adipose tissue.

Main Methods:

• Analysis of signaling pathways including Ca2+-ERK-CREB and Smad1/5 phosphorylation.
• Investigation of IL-11's downstream effects on Sost and Wnt signaling.
• Examination of IL-11's impact on adipogenesis and adipolysis in adipose tissue.

Main Results:

• Mechanical loading and PTH stimulate IL-11 transcription via distinct pathways involving CREB and Smad1/5.
• Increased IL-11 suppresses Sost expression and enhances Wnt signaling, promoting bone formation.
• Exercise-induced IL-11 enhances adipolysis and reduces adipogenic differentiation, linking bone health and energy metabolism.

Conclusions:

• IL-11 acts as a crucial mediator in bone formation, integrating signals from mechanical loading and PTH.
• Exercise-induced IL-11 establishes a bone-fat axis, supplying energy for muscle contraction while promoting bone mass.
• This mechanism highlights a coordinated physiological response to exercise, benefiting both skeletal integrity and energy homeostasis.