We are trying to understand the biological phenomena as a complex network system with a hierarchical architecture. Since typical dynamics of most biological systems are not linear, merely understanding simple molecular events cannot lead us the holistic understanding of the cellular responses to the specific stimuli under various contexts. To achieve the ultimate goal of our laboratory, which is the holistic understanding of the dynamics of complex biological system to overcome disease such as cancer, we apply various approaches to investigate complex system of living organism. To delineate various disorders, we focus on the intracellular signaling networks for proliferation, inflammation, apoptosis, senescence, based on in vitro, in vivo and in silico techniques.
지난 수십 년 간 사람의 각종 병리학적 증상을 치료하기 위한 생리활성 단백질들의 발견과 함께, 모노클로널 항체 (monoclonal antibodies), 인슐린, 사이토카인 (cytokine) 등의 활성 단백질들을 주입하여 치료하는 생의학 (Biopharmaceuticals) 분야가 많은 발전을 이루어왔다. 생의학 약품은 우리 생활에 있어서 막대한 영향을 미치고 있지만, 많은 약품의 개발에도 불구하고, 단백질은 세포 내부로 자연적으로 들어가지 못한다는 특성 때문에, 아직까지 거의 모든 생의학 약품들은 세포 겉에서 작용하는 것에 그치고 있다.
한 편, 모든 다세포 생명체 내에는 자연적으로 세포 간의 핵산이나 단백질 등의 전달을 위한 운반체가 존재한다. 세포 간 신호전달의 주요한 매개체로 사용되는 이 물질은 세포외소낭 (Extracellular Vesicles, EV)이라고 부르며, 지질이중층으로 둘러 쌓여있는 구형의 물질이다. 세포외소낭은 구조적, 생화학적 특성에 따라 다양하게 분류할 수 있는데, 대표적으로 연구되고 있는 세포외소낭들에는 100 – 1000 nm 크기를 가지며 세포막에서 발아되는 미세소포체 (Microvesicles)와 50 – 200 nm 크기를 가지며 세포 내부의 다소포체에서 파생되는 엑소솜 (Exosome)이 있다.
Despite the long list of therapeutic proteins available for treating various human diseases, the vast majority of commercial protein-based drugs, such as cytokines, hormones, and monoclonal antibodies, have been limited to extracellular mechanisms of action. Many intracellular proteins with great potential as biopharmaceutical drugs have been identified; however, many of the challenges associated with intracellular protein delivery in vivo have yet to be solved. On the one hand, there are cell-derived natural carriers that can deliver nucleotides and proteins and participate in intercellular communication. These key mediators are called extracellular vesicles (EV) and have a spherical shape which is composite of lipid bilayers. EVs can be classified according to their structural and biochemical properties, there are two representative EVs. 1) Microvesicles: which have hydrodynamic sizes of 100 – 1000 nm and are budded from the cell plasma membrane. 2) Exosoes: which have hydrodynamic sizes of 50 – 200 nm and are originated from internal endocytic compartments and multi-vesicular bodies. In our laboratory, by integrating a reversible PPI module controlled by blue light with the endogenous process of exosome biogenesis, we were able to successfully load cargo proteins into newly generated exosomes. Using this method, we can easily produce protein-loaded exosomes by a simple transfection and blue LED illumination. Not only this method is the first technology that can stably load cargo proteins into extracellular vesicles, but also this technique can approach to naturally and massively obtain protein-loaded exosomes. We succeed the intracellular delivery of various functional proteins such as Cre recombinase in the target cells and in vivo, and are now testing the EXPLOR drugs for treating various human diseases. We expected that the advantages of cell-derived materials can provide innovative solutions against the challenges associated with intracellular protein delivery in vivo.