Deficiency of myotubularin-related protein 14 influences body weight, metabolism, and inflammation in an age-dependent manner

Yin Lv, Lu Xue, Congli Cai, Qing-Hua Liu, Jinhua Shen

Myotubularin-related protein 14 (MTMR14) is a novel phosphoinositide phosphatase with roles in the maintenance of normal muscle performance, autophagy, and aging in mice. Our initial pilot study demonstrated that MTMR14 knock out (KO) mice gain weight earlier than their wild-type (WT) littermates, which suggests that this gene may also be involved in metabolism regulation. The present study evaluated the role of MTMR14 in the development of aging-associated obesity. We found that aged MTMR14 KO mice fed a normal chow diet exhibited increased serum triglyceride, total cholesterol, and glucose levels compared to age-matched WT controls. Lipid accumulation was also increased in aged KO mice. Several inflammatory cytokines and adipokines were dramatically dysregulated in the metabolic tissues of aged MTMR14 KO mice compared to control mice. Circulating inflammatory cytokines were significantly elevated and plasma adipokine levels were abnormally regulated in aged MTMR14 KO mice. These data suggest that MTMR14 deficiency caused a late-onset inflammation and metabolic dysfunction. Further study demonstrated that this exacerbated metabolic dysfunction and inflammation may be regulated by the phosphoinositide 3 kinase/protein kinase B and extracellular signal-regulated protein kinase signaling pathways. Our current research suggests that MTMR14 deletion induces overweight and adult obesity accompanied by chronic inflammation in an age-dependent manner.