Playing Molecular Tetris to Help Improve the Lives of Millions

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By Tom Linder
Photo of 91制片厂 Tech Associate Professor of Biology Oscar Juarez in front of a glass window with his arms folded.

Cholera is an acute gastrointestinal disease that produces rapid dehydration and affects millions of people around the globe, mostly children.

This threat has been made even more dire in recent decades, as the gastrointestinal disease鈥攃aused by the bacterium Vibrio cholerae鈥攈as grown increasingly resistant to antibiotics.

鈥淚n a recent study in sub-Saharan Africa and many other places cholera is prevalent, it is shown that 100 percent of the clinical samples they have are resistant to multiple antibiotics,鈥 says 91制片厂 Tech Associate Professor of Biology Oscar Juarez. The impact of this disease was evident in Haiti, where a cholera outbreak produced a collapse of the health care system in the country.

Juarez and his team at 91制片厂 Tech鈥擯h.D. students Ming Yuan (Ph.D. MBB 鈥24) and Yuyao Hu (Ph.D. BIOL Candidate ), postdoc Martin Andres Gonzalez Montalvo, and Assistant Professor of Biology Karina Tuz鈥攈补惫别 , demonstrating that it is effective to combat multi drug-resistant strains of cholera.

Previously, clofazimine had been used to treat leprosy and tuberculosis. The drug鈥檚 manufacturer, however, discontinued production for the United States nearly a decade ago.

Juarez鈥檚 lab focused on understanding how cholera survives in the human body, identifying a protein called NQR that plays a central role in the disease鈥檚 ability to produce energy.

Clofazimine works by inhibiting NQR, which cuts off the bacteria鈥檚 energy supply and, ultimately, would destroy the infection.

鈥淥ur study shows that NQR is super important for Vibrio cholerae to produce energy. We identified where exactly it is that clofazimine binds to,鈥 says Juarez, adding: 鈥淭he cell has thousands of different proteins. What we did was identify the target of clofazimine in Vibrio cholerae, which is NQR.鈥

Unlike typical drug discovery efforts鈥攚hich often involve testing thousands of molecules鈥擩uarez鈥檚 team already knew which type of molecule with inhibitory properties that it was looking for. Because of this prior knowledge, the team only had to test around 20 molecules instead of the typical hundreds of thousands.

鈥淲hat we鈥檙e doing is actually engineering drug design, because we know the properties of molecules that should have inhibitory effects over NQR and over Vibrio cholerae,鈥 says Juarez. 鈥淲e have enough information to be able to predict the type of molecules that have inhibitory properties and to speed up drug discovery and drug design.鈥

The next step in repurposing clofazimine to treat cholera most effectively will involve modifying it鈥攕pecifically, grouping chemicals in different positions in order to make it a better inhibitor.

It鈥檚 a process Juarez playfully refers to as molecular Tetris.

鈥淲hen you鈥檙e playing Tetris, you鈥檙e making something fit in a specific position,鈥 says Juarez. 鈥淲hat we鈥檙e doing is taking the structure of clofazimine鈥攚hich fits well into the pocket of a protein鈥攁nd if we include another chemical group that makes it fit better, then it will be more potent.鈥

The biggest perk of repurposing an already-known drug? Clofazimine is already approved by the U.S. Food and Drug Administration, which saves years and billions of dollars of trials and research.

鈥淭he approval requires about $2.1 billion and about 10 years of testing,鈥 says Juarez. 鈥淭he three levels of clinical trials in humans, we may skip them, because we already know clofazimine is safe.鈥

As a result, a safe, effective treatment for multi drug-resistant cholera could be just around the corner, at the cost of around $20 per dose. Juarez and his team are in the process of patenting the use of clofazimine to treat cholera.

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