AI-designed molecular switch uses caffeine to control engineered cells

For many of us, a warm cup of coffee is how we start our day. For Texas A&M Health researchers, it may also offer a new way to control engineered cells in future medicines.

A team at the Texas A&M Health Institute of Biosciences and Technology has developed an artificial intelligence-designed molecular switch that uses caffeine to rapidly separate engineered proteins inside living cells and trigger cellular responses on demand. The platform, called CODS, short for caffeine-operated dissociation system, could help scientists build safer and more controllable gene and cell therapies.

AI as a molecular architect

To build CODS, the team used AI-guided protein design to create a small synthetic binder which recognizes a caffeine-responsive protein module. The binder holds the system together when caffeine is absent, and when caffeine is added, the proteins separate.

In this way, CODS acts like a molecular clasp. Without caffeine, the clasp stays closed. With caffeine, the clasp opens.

"Many genetically-encoded molecular tools act like accelerators," Wang said. "CODS gives us something closer to a brake or pause button."

High-performance computing

The AI-driven design process required substantial computational power. The team used protein-design algorithms and molecular simulations to identify, evaluate and refine synthetic binders before testing the most promising candidates in living cells.

"High-performance computing was essential for this project," Zhou said. "AI protein design is computationally demanding. The Texas A&M HPRC service helped us move from a conceptual idea to a functional molecular switch much faster."

The resulting system responded to very low caffeine concentrations, worked within minutes and could be reversed repeatedly by adding or removing caffeine.

Controlling genes, cell death and immune cells

The researchers demonstrated CODS in three major ways.

First, they used it to control gene activity. Without caffeine, an engineered gene circuit remained active. When caffeine was added, CODS separated the target proteins needed to keep the gene turned on, sharply reducing gene activity. Removing caffeine allowed the system to recover.

Second, the team used CODS to control programmed cell death. By rewiring a cell-death protein with the caffeine-responsive switch, they created a system in which caffeine could trigger inflammatory cell death, known as pyroptosis. This could help scientists study inflammation and may one day support the design of therapeutic cells that can be eliminated when needed.

Using CODS, this Texas A&M team built a split CAR system that remains active when caffeine is absent but remains passive when caffeine is added. In laboratory tests, caffeine strongly reduced CAR T-cell activation, suggesting that CODS could become a practical safety OFF switch for engineered immune cells.

Beyond coffee: Toward programmable medicine

Zhou emphasized that caffeine itself is not a cancer treatment. Instead, caffeine serves as a safe and familiar signal that can communicate with specially engineered cells.

"Coffee will not replace medicine," Zhou said. "But caffeine can help us imagine medicines that are more controllable, more responsive and safer for patients."

The broader advance is the use of AI to design new proteins that behave in ways nature does not readily provide. Similar strategies could eventually be used to build switches controlled by other familiar molecules, over-the-counter drugs or clinically approved medicines.

Before CODS can move toward clinical use, the system will need further testing in therapeutic cells, animal models and disease-relevant settings. Still, the study marks an important step toward programmable medicine in providing a framework for designing therapies that can be adjusted after they are delivered.

"Powerful therapies need powerful control," Zhou said. "By combining AI-designed proteins, high-performance computing and familiar small molecules, we are building a new language for communicating with engineered cells."

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Texas A&M University

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