Autophagy Induced by Trehalose Alleviates Apoptosis of Human Aortic Endothelial Cells After Cryopreservation

Trehalose improves palmitic acid-induced apoptosis of osteoblasts by regulating SIRT3-medicated autophagy via the AMPK/mTOR/ULK1 pathway

Accumulation of lipid substances decreased the activity of osteoblasts. Trehalose is a typical stress metabolite to form a protective membrane on cell surface which has been demonstrated to regulate lipid metabolism. This activity of Trehalose indicates the potential effect of osteoporosis treatment. Our study aimed to determine the therapeutic effect of Trehalose in high fat-induced osteoporosis. We used palmitic acid (PA) to mimic the state of high fat and observed the apoptosis ratio of osteoblasts increased. After adding Trehalose, the apoptosis ratio decreased obviously. Autophagy is a regulatory means involved in the process of apoptosis. We detected the autophagy protein and found that the expression of Beclin-1, Atg5, and LC3 II increased, and p62 decreased after Trehalose treatment. When adding an autophagy inhibitor (3-MA), the expression of Beclin-1, Atg5, and LC3 II decreased, and p62 increased. These results indicated autophagy was an important factor involved in the preventive effect of Trehalose in PA-induced apoptosis. SIRT3 is a mitochondrial gene that can inhibit apoptosis, which has been reported to promote autophagy. We used SIRT3-siRNA to silence the expression of SIRT3 and found the effect of Trehalose was counteracted. The apoptosis ratio increased and the expression of Beclin-1, Atg5, and LC3 II decreased, p62 increased. Additionally, we also fed the mice with a high-fat diet (HFD) and intragastrical Trehalose. The results showed that Trehalose could inhibit the bone mass loss with HFD. Our study revealed the effect and mechanism of Trehalose in the treatment of osteoporosis.

Exploring the mechanism of trehalose: dual functions of PI3K/Akt and VPS34/mTOR pathways in porcine oocytes and cumulus cells†

Autophagy, an intracellular recycling system, is essential for the meiotic maturation of porcine oocytes. Multiple studies, sought to reveal the precise mechanism employed, commonly used autophagy inducers, such as rapamycin, which is a mammalian target of rapamycin (mTOR) inhibitor. However, it has a limitation as mTOR plays various roles in cell growth and metabolism beyond autophagy. Trehalose has been reported as a novel mTOR-independent autophagy inducer in many cells. Furthermore, our previous study demonstrated that trehalose supplementation during in vitro maturation of porcine oocytes improves the developmental competence of parthenogenetic embryos possibly via autophagic activation, whereas the underlying mechanisms remain unclear. Therefore, the aim of this study was to address this issue. In this study, we found that trehalose plays a role as an autophagy activator by autophagic flux assay and determined that it promotes PI3K/Akt inhibition and VPS34/mTOR activation by immunoblotting, both in cumulus cells (CCs) and oocytes. However, it is interesting to note that these effects caused by trehalose were worked totally varying between CCs and oocytes. In CCs, the autophagy was activated through the improvement of lysosomal function/autophagic clearance viability by upregulation of coordinated lysosomal expression and regulation genes via PI3K/Akt inhibition. Whereas in oocytes, autophagy was activated via VPS34 induction which directly influences autophagosome formation, and the precise meiotic process was ensured via Akt inhibition and mTOR activation. Taken together, this study provided evidence that trehalose could be used as an autophagy inductor during porcine oocyte maturation based on the revealed mechanism.