Our lab focuses on regenerating damaged or diseased tissue by reprogramming genetic regulation and processes. Personally I’d like to fantasize our work as synthesizing tiny protein “robots” that manipulate gene expression in the cell. Specifically, I am working on regeneration of smooth muscle cells.
Smooth muscle cell is, according to Wikipedia, “an involuntary non-striated muscle”. It basically refers to the muscle that composes a large portion of blood vessels, lymphatic vessels, bladder, gastrointestinal system, and respiratory tract. These organs serve important functions for human body. So regeneration of smooth muscle is of pivotal importance for the treatment of various diseases and damages related to smooth muscle. My goal is to transform easily accessible cells, fibroblasts, into smooth muscle cells.
It is known that some transcription factors are very important for cell lineage commitment. Therefore, in theory I can change the cell fate by manipulating the expression of some specific transcription factors. The decision for smooth muscle cells is largely based on a co-activator called myocardin. It is known to be the master regulator for smooth muscle cells. When it binds to serum response factor, they together activate lots of smooth muscle specific genes and the cell differentiate into smooth muscle cell. However, when a co-repressor called elk-1 binds to serum response factor, they leads to proliferation. Essentially, myocardin and elk-1 serve as the genetic switch between differentiation and proliferation by competing for the common docking site. I am trying to activate the expression of endogenous myocardin gene to see if I can transform fibroblast into smooth muscle cell. I am also trying to repress elk-1 so that it does not compete with myocardin. Finally, I am also trying to activate the expression of a microRNA miR-145. There seems to be a positive feedback loop for myocardin and miR-145. Hopefully simultaneous activation of myocardin and miR-145 will increase the chance of reprogramming.
I am going to repress or activate the gene expression by utilizing a very cool and new technology, CRISPR/Cas9 system. The protein Cas9 incorporate a small RNA fragment called gRNA. The cool part is that Cas9 is able to precisely target a specific region of DNA by complimentary base pairing between the gRNA and genomic DNA. Therefore, I am able to target my gene of interest by just changing the sequence of gRNA. I am just done with cloning the gRNA that target the promoter region of myocardin and elk-1. I’m excited!
