Human LAMP2 peptide

Lysosomes are acidic and highly dynamic organelles that are essential for macromolecule degradation and many other cellular functions. However, little is known about lysosomal function during early embryogenesis. Here, we found that the number of lysosomes increased after fertilization. Lysosomes were abundant during mouse preimplantation development until the morula stage, but their numbers decreased slightly in blastocysts. Consistently, the protein expression level of mature cathepsins B and D was high from the one-cell to morula stages but low in the blastocyst stage. One-cell embryos injected with siRNAs targeted to both lysosome-associated membrane protein 1 and 2 (LAMP1 and LAMP2) were developmentally arrested at the two-cell stage. Pharmacological inhibition of lysosomes also caused developmental retardation, resulting in accumulation of lipofuscin. Our findings highlight the functional changes in lysosomes in mouse preimplantation embryos.

This study aimed to investigate the effects of quercetin that is natural functional component in food on lysosome damage-mediated autophagy dysfunction in ALD and its possible underlying mechanisms. The C57BL/6J mice were divided into four groups and pair-fed with either regular or ethanol-containing Lieber De Carli liquids diets for 15 weeks. Quercetin was received by gavage. According to the purpose of experiments, primary hepatocytes were pretreated with various pharmacological reagents. Results showed that quercetin alleviated chronic ethanol consumption induced liver injury and autophagic flux suppression. Quercetin decreased the abnormal LC3-II and p62 accumulation and increased the expression of LAMP1, LAMP2 and Rab7. Besides, quercetin reversed the inhibition of TFEB nuclear translocation incited by ethanol and exhibited similar effect to Torin 1 (mTOR activity inhibitor) which could promote TFEB nuclear translocation. Thus, regulating mTOR-TFEB pathway may be a major mechanism of quercetin for ameliorating lysosomal autophagy dysfunction induced by ethanol.