Patterned, Responsive Cellular Therapies Using Novel Mammalian Cellular Regulator Systems

Abstract General Biologics, Inc. Proposal D2-2580 STTR Phase II  Our goal is to use the tools of modern synthetic biology to develop a set of regulated mammalian genetic circuits that can produce one or more therapeutic proteins to provide rapid temporary treatment for acute injuries and trauma on the battlefield or for civilian disease needs.  Our genetic circuits will be administered in an injectable form of DNA together with compounds designed to aid the DNA to bind to and enter cells, and to become established in the nucleus.  Our genetic circuits will have at least three key features: 1) They will be silent until a specific signal active activates the circuit to express the desired therapeutic protein.  This will be accomplished by using promoters that function only when they are specifically induced by the appropriate signal.  2) They will not integrate into chromosomes at a significant frequency.  This will be accomplished by using a linear DNA format.  3) They will be designed to be removed from the patient after they have performed their function.  This will be accomplished by including a gene encoding a protein that will kill each transfected cell (and only transfected cells!) upon receiving a specific signal. While the warfighter remains healthy, a circuit would be in an “off” state.  If a soldier is wounded and infected, and is at risk of becoming septic but cannot be immediately medically evacuated or stabilized, a specifically responsive genetic circuit would activate anti-inflammatory responses as needed.  If a soldier is irradiated, a genetic circuit would activate synthesis of proteins that prevent massive cell death.  If a soldier becomes hypoxic due to blood loss or high altitude, a genetic circuit would express a protein that prevents cell death due to hypoxia and also increases red blood cell production.  This approach could be extended to performance enhancement, exposure to organophosphate nerve agents, and psychological trauma. The ideal design for our genetic circuits will be a DNA complex that can be directly injected into the warfighter before or after injury.  This is our goal.  A less ideal but technically easier goal is to withdraw cells from the warfighter (e.g. white blood cells), engineer the cells, and put them back.  This could be useful prophylactically, but is less useful after injury.  Another goal is to ensure that the circuit DNA will not integrate into the chromosome at a significant frequency, thus reducing the probability of inserting into a tumor suppressor and causing cancer.  To attain this goal, we will focus on linear DNA formats, as it is well known that circular DNAs can integrate at dangerous frequencies.  In order to be removable after the appropriate functional time period, a “kill switch” will be incorporated in the circuit that causes death of each transfected cell.  In Phase I we will focus primarily on circuit design and delivery.  In Phase II we will shift focus to more small animal studies.