My long term goal is to reveal novel functions of autophagy in normal cellular physiology and pathology through the analysis of the double-membrane autophagosome and autophagic machinery using cell and animal models.
Autophagy regulates cellular metabolism to protect cell from stress-caused damages through degradation machinery. Over 20 autophagy related genes (Atg) are responsible for two major ubiquitination-like conjugation systems. Accumulating evidence shows that autophagosome selectively recruits cargos (aggregated protein, damaged organelle, pathogen and microRNA) in cytosol, followed by fusion with the lysosome for degradation. In our studies, we are the first to reveal that autophagosome selectively recruit oncogenic microRNA (miR-224) and protein (Cyclin D1) to regulate the tumorigenesis of hepatocellular carcinoma. These data indicate that autophagosome recognizes and recruits specific molecules followed by degradation.
Another function of autophagy called secretory autophagy (also called autosecretion or type III secretion) is getting more attention. Different from the traditional degradative autophagy, the recruited cytosolic molecules are carried by the double-membrane autophagosome and exported to extracellular environment. However, physiological and pathological role of secretory autophagy remains poorly understood.
1. Identification of the cargos delivered to extracellular
environment through secretory autophagy.
2. Clarification of the relationship between degradative and secretory autophagy.
3. Regulation of secretory autophagy for the therapy of tumorigenesis, diabetes mellitus and other diseases.
We have identified a group of the proteins related to the vesicle-mediated transportation as well as the extracellular cargos by LC/MS/MS proteomics analysis. In the future, we would like to validate these candidate proteins and clarify their functions under normal physiological and pathogenic conditions. For cancer studies, we have established several orthotropic cancer models (liver, lung and bladder) and metastatic animal models (lung to lung and tail vein). For diabetes mellitus, streptozotocin (STZ) induced type-I DM and high fat diet induced type-II DM mice models were also developed in this lab.