A prepared anti-MSTN polyclonal antibody reverses insulin resistance of diet-induced obese rats via regulation of PI3K/Akt/mTOR&FoxO1 signal pathways.

Suppression of myostatin (MSTN) is associated with skeletal muscle atrophy and insulin resistance. However, the mechanisms by which MSTN regulates insulin resistance are not well known. We have explored the signaling pathways through which MSTN regulates insulin resistance in diet-induced obese rats using a polyclonal antibody for MSTN. The anti-MSTN polyclonal antibody significantly improved insulin resistance and whole-body insulin sensitivity, decreased MSTN protein expression in muscle samples by 39% in diet-induced obese rats. Furthermore, the anti-MSTN polyclonal antibody significantly enhanced PI3K activity (140%), Akt phosphorylation (86%), GLUT4 protein expression (23%), the phosphorylation of mTOR (21%), and inhibited the phosphorylation of FoxO1 (57%), but did not affect the phosphorylation of GSK-3ß. Thus, suppression of MSTN by the anti-MSTN polyclonal antibody reverses insulin resistance of diet-induced obesity via MSTN/PI3K/Akt/mTOR and MSTN/PI3K/Akt/FoxO1 signaling pathways.

[Construction of gene vaccine of myostatin fusion with T-helper epitope and its effects on forelimb grip in immunized mice].

OBJECTIVE: To further study the therapy of wasting muscle by myostatin as a new targets, the eucaryotic expression vector coupled the foreign T-helper epitope of tetanus toxin (TT) to the N terminus of myostatin was constructed, and the effects of the gene vaccine on forelimb grip were tested in immunized mice. METHODS: A DNA fragment encoding the TT epitope followed by the N terminus of mature myostatin (330bp) was synthesized. The eucaryotic expression vector of myostatin was constructed and the chinese hamster ovary (CHO) cells were infected with the recombinant plasmids pVAC-TT-Ms by liposome transfection according to routine laboratory procedure. The myostatin expression was tested by cell immunofluorescence technique in transfected CHO. The forelimbs grip were tested in immunized mice with myostatin gene vaccine. RESULTS: The eucaryotic expression vector of myostatin coupled TT epitope was constructed successfully through the restriction analysis and sequencing. The recombinant plasmids pVAC-TT-Ms met quality criterion as gene vaccine by analysis OD260/280 and electrophoresis. The myostatin expression was detected obviously in transfected CHO. The forelimb grip in immunized mice had an obvious increase. The average value of forelimb grip of the mice immunized with pVAC-TT-Ms was about 29.88% greater than that of control mice. CONCLUSION: The construction of eucaryotic expression vector of myostatin coupled TT epitope is successful in expression for recombinant human mature peptide of myostatin. The gene vaccine of myostatin meet quality criterion. The immunized mice has an obvious increase in forelimb grip.