(2mb) Programmable Synthetic Circuits for Smart Therapeutics

I envision a generation of engineered cells encoding synthetic protein circuits that can sense, interface, and rewire complex biological networks creating opportunities for tissue engineering and immuno-engineering. Tissue engineering has shown promising therapeutic potential; however, the immune system remains a key barrier that must be overcome for long-term cellular engraftment. Current strategies focused on local immune modulation often generate acute responses, largely due to their inability to dynamically respond, or finite reservoir of immune-modulating biologics. In comparison, the field of synthetic biology is uniquely suited to provide the means for probing and controlling such interactions using engineered cells with synthetic circuits that can respond to combinatorial environmental inputs, interrogate natural systems, and produce controlled therapeutic responses. Since the emerging consensus is that the spatiotemporal control of immune-modulating biologics (i.e. cytokines, chemokines, and growth factors) are important for achieving immune homeostasis, engineered cells with synthetic protein circuits can close the technological gap for controlling the dynamic expression of these intercellular signals.

Developing mammalian synthetic biology approaches for tissue engineering applications requires broad interdisciplinary expertise to both envision and engineer synthetic signal transduction pathways to program cell behaviour, as well as the ability to predict and characterize their behaviour within biological systems. My research vision combines my past expertise to engineer synthetic transduction pathways to control cell behaviours to develop “smart” therapeutics, which will enable engineered cells to interface with complex biological systems, such as the immune system. My initial research goals include i) the generation of protein sensors to sense changes in internal cell states or the external microenvironment, (ii) the use engineered cells to model cell-cell communications to elucidate the dynamics and expression of key signals that govern fibrosis and immune rejection, and iii) applying the synthetic protein circuits generated in the first two research thrusts to improve cell transplantation, in vivo. Together, this work promises to reveal new insights on the dynamic signalling between transplanted cells and the host, with the immediate applications for development of next-generation cellular therapeutics.

Research Experience:

My doctoral and postdoctoral training have prepared me to lead this research program. I completed my PhD with Prof. Michael Sefton at the University of Toronto, where I used principles in tissue engineering, regenerative medicine, and biomaterials to develop platforms to improve vascularization of the subcutaneous space for islet transplantation. To overcome the avascular properties of the subcutaneous space, I embedded pancreatic islets within collagen rods coated by endothelial cells to support islet engraftment through vascularization (Vlahos et al, PNAS 2017). Since islet compositions and size are two critical parameters for islet survival, I also developed a pseudo-islet platform that offered a degree of control not possible with native islets (Vlahos et al, Biomaterials 2020). Furthermore, I used a catheter coated with an angiogenic methacrylic acid-based co-polymer to pre-vascularize the subcutaneous space and lower the therapeutic dosage required to achieve normoglycemia (Vlahos et al, Biomaterials 2021).

As a Human Frontier Science Program long-term fellow with Prof. Xiaojing Gao at Stanford University, I developed a generalizable platform (RELEASE) to enable the programmable control of intercellular signalling using synthetic protein circuits in mammalian cells (Vlahos et al, Nature Comms 2022). I am now expanding the RELEASE platform to enable logic operations and quantitative processing in a compact single transcript design, amenable for their use in viral vectors with limited packaging capabilities (Vlahos et al, in prep). In parallel, I have adapted the RELEASE platform to function as a high-throughput assay with the goal of probing the role of transmembrane domains on protein surface expression (Vlahos* and Call*, in prep). Using this high-throughput analysis, we are developing machine learning algorithms to determine the key design parameters of transmembrane domains to help guide future engineering of synthetic signalling platforms, such as CAR-T receptors and other synthetic receptors. Collectively, my work has helped expand the synthetic protein circuit toolkit and highlight its potential for therapeutic applications.

Complete list of my published work: https://tinyurl.com/ynf4kawu

Teaching Interests and Experience:

I find teaching emotionally and intellectually fulfilling, and an important quality of a good researcher. Through teaching and mentoring, my goals have always been to provide students with a body of knowledge, nurture their critical thinking skills and teach them how to apply basic concepts to solve more complex problems. I believe it is critical to be receptive to feedback and recognize when certain approaches are more applicable, such as using lecture slides, instructional videos, or learning through discussion.

Throughout my graduate and postdoctoral studies, I have become well-versed in various disciplines such as tissue engineering, regenerative medicine, biomaterials, biochemistry, synthetic biology, protein engineering and cell biology. My strong foundation in biochemistry and biology with my research experience in tissue engineering, biomaterials, and synthetic biology, prepares me to teach core biochemistry and biomedical engineering courses such as molecular biology, cell biology, and protein engineering. I am ready to lead advanced courses that discuss and critically analyze literature, especially related to biomaterials, tissue and protein engineering, and synthetic biology. Furthermore, I will develop unique and interdisciplinary elective courses at the interface of synthetic biology, protein engineering, cell delivery and biomedical engineering.

Outreach Interest and Experience:

Throughout my studies I have had the privilege to receive world-class training, and I believe that it is important to give back, when possible, to students that may be less fortunate. During my graduate studies, I was involved in various outreach activities such as BME Biomedical Engineering and Me (iBEAM) and Stem Cell Talks Toronto. Both programs were designed to expose high school students to the field of STEM. I designed interactive workshops, developed hands-on activities, and case studies, highlighting different topics in stem cell biology and tissue engineering. Currently I am an Instructor for Science Clubs International, where I designed a month-long course designed to introduce STEM students to Biomedical Engineering and its translational potential for therapeutic applications. From these experiences, I learned that motivation was a great tool to facilitate effective learning and used these experiences to further develop my teaching and mentorship style.