mRNA Levels Of mTOR Research Articles

Mammalian target of the rapamycin pathway is involved in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease associated with an increased risk of type 2 diabetes and cardiovascular disease. Many factors may contribute to NAFLD development and progression, but the exact mechanisms are still not fully understood. In this study, Sprague-Dawley rats were fed either a standard diet (control group), a high-fat diet for 8 weeks (the HFD-8 group) or a high-fat diet for 16 weeks (the HFD-16 group). The HFD animals showed high levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and insulin resistance index (Homa-IR). Mild and severe steatosis was found in both the HFD-8 and HFD-16 groups, respectively. Compared with the controls, mRNA levels of mTOR, S6K1, IL-1α, IL-6 and TNFα were significantly increased in the HFD-8 and HFD-16 groups. IRS-1 mRNA was significantly increased in the HFD-8 group, but not in the HFD-16 group. The protein levels of mTOR, pmTOR(Ser2448), S6K1, pIRS-1(Ser307), IL-1α and IL-6 were significantly increased in the HFD-8 and HFD-16 groups. The protein levels of pmTOR(Ser2448) and IL-1α were significantly higher in the HFD-16 group compared to those in the HFD-8 group. However, the protein expression level of mTOR did not differ significantly between the HFD-8 and HFD-16 groups. The pIRS-1(Tyr102) level was significantly lower in both the HFD-8 and HFD-16 groups when compared to that in the control group, and the pIRS-1(Tyr102) level was significantly lower in the HFD-16 group compared to that of the HFD-8 group. pmTOR(Ser2448) was positively correlated with the TNFα mRNA level, and pIRS-1(Ser307) was positively correlated with pmTOR(Ser2448), TNFα, S6K1 and mTOR. pIRS-1(Tyr102) was negatively correlated with pmTOR(Ser2448), TNFα, S6K1 and mTOR. These data indicate that mTOR contributes to insulin resistance and chronic liver inflammation, and may play an important role in the development and progression of NAFLD.

The role of MTOR in mouse uterus during embryo implantation

Mammalian target of rapamycin (MTOR) is a protein kinase that plays a central role in cell growth and proliferation. It is a part of the signaling network transmitting growth factor signaling to translational control. Previous studies have shown that MTOR is involved in embryo implantation, but its expression in the uterus and its role in implantation are unclear. Here, we have investigated the expression and role of MTOR in mouse uterus during early pregnancy. RT-FQ PCR showed that the mRNA levels of Mtor in endometria of pregnant mice were higher than those of nonpregnant mice. The mRNA levels in the pregnant mice gradually increased from D3 of pregnancy, reached maximum on D5, and then declined afterward. In situ hybridization and immunohistochemical analysis showed that the mRNA and protein of MTOR were mainly located in stromal cells. The levels of the expressed MTOR protein correlate with those of mRNA. The number of implantation sites was greatly decreased by the intrauterine injection with rapamycin in the early morning of D4 of the pregnancy. These findings suggest that MTOR may play an important role in embryo implantation in mice.