Dysregulated transforming growth factor-beta mediates early bone marrow dysfunction in diabetes

Area of Science:

• Biomedical Science
• Stem Cell Biology
• Endocrinology

Background:

• Diabetes mellitus is known to affect multiple organs, including the eyes, kidneys, heart, and brain.
• Previous research indicates that diabetes promotes adipogenesis (fat cell formation) in bone marrow and depletes vascular regenerative stem cells.
• Early molecular and structural changes in the bone marrow due to diabetes remain incompletely understood.

Purpose of the Study:

• To investigate the early, time-dependent alterations in bone marrow following the onset of diabetes.
• To identify the molecular mechanisms underlying diabetes-induced changes in bone marrow stem cell populations.

Main Methods:

• Spatio-temporal examination of bone marrow in a mouse model of short-term diabetes.
• Analysis of adipogenesis and stem cell populations.
• Investigation of transforming growth factor-beta (TGFB) signaling pathways using human bone marrow-derived mesenchymal progenitor cells.

Main Results:

• Short-term diabetes induces significant structural and molecular changes in the bone marrow, notably enhanced adipogenesis in mouse tibiae.
• Increased adipogenesis occurs before any observable depletion of marrow-resident stem cells.
• Suppressed TGFB signaling was identified as a key molecular event associated with enhanced adipogenesis.

Conclusions:

• Diabetes initiates bone marrow changes, including increased fat cell differentiation, even before stem cell depletion occurs.
• The transforming growth factor-beta (TGFB) pathway, specifically via TGFB-activated kinase 1 (TAK1), plays a crucial role in suppressing adipogenic differentiation.
• These findings suggest that targeting the TGFB pathway could be a therapeutic strategy to preserve stem cell function in diabetic patients.