The extracellular matrix protein MAGP1 supports thermogenesis and protects against obesity and diabetes through regulation of TGF-β

CS Craft, TA Pietka, T Schappe, T Coleman… - Diabetes, 2014 - Am Diabetes Assoc
CS Craft, TA Pietka, T Schappe, T Coleman, MD Combs, S Klein, NA Abumrad, RP Mecham
Diabetes, 2014Am Diabetes Assoc
Microfibril-associated glycoprotein 1 (MAGP1) is a component of extracellular matrix
microfibrils. Here we show that MAGP1 expression is significantly altered in obese humans,
and inactivation of the MAGP1 gene (Mfap2−/−) in mice results in adipocyte hypertrophy and
predisposition to metabolic dysfunction. Impaired thermoregulation was evident in Mfap2−/−
mice prior to changes in adiposity, suggesting a causative role for MAGP1 in the increased
adiposity and predisposition to diabetes. By 5 weeks of age, Mfap2−/− mice were …
Microfibril-associated glycoprotein 1 (MAGP1) is a component of extracellular matrix microfibrils. Here we show that MAGP1 expression is significantly altered in obese humans, and inactivation of the MAGP1 gene (Mfap2−/−) in mice results in adipocyte hypertrophy and predisposition to metabolic dysfunction. Impaired thermoregulation was evident in Mfap2−/− mice prior to changes in adiposity, suggesting a causative role for MAGP1 in the increased adiposity and predisposition to diabetes. By 5 weeks of age, Mfap2−/− mice were maladaptive to cold challenge, uncoupling protein-1 expression was attenuated in the brown adipose tissue, and there was reduced browning of the subcutaneous white adipose tissue. Levels of transforming growth factor-β (TGF-β) activity were elevated in Mfap2/ adipose tissue, and the treatment of Mfap2/ mice with a TGF-β–neutralizing antibody improved their body temperature and prevented the increased adiposity phenotype. Together, these findings indicate that the regulation of TGF-β by MAGP1 is protective against the effects of metabolic stress, and its absence predisposes individuals to metabolic dysfunction.
Am Diabetes Assoc