Mizzou scientists explore new frontiers in virus defense

Viruses and bacteria are always trying to sneak into our bodies, but researchers at the University of Missouri are discovering that our own biology may already hold the keys to fighting off some of the deadliest infectious threats.

At the center of their latest discovery are defensins, tiny proteins with powerful antimicrobial potential. These naturally occurring proteins serve as part of our immune system’s first response team but sometimes can’t mount a significant defense at specific sites of infection. Now, researchers at Mizzou’s College of Agriculture, Food and Natural Resources are uncovering how these proteins might be harnessed more effectively.

In a recent study, microbiologists Piyush Baindara and Dinata Roy discovered that certain defensins could block the virus that causes COVID-19 (SARS-CoV-2) from entering human cells.

“Viruses always seek out a specific receptor to enter into our cells, similar to how a key fits into a lock,” Baindara, a senior research associate, said. “In the case of SARS-CoV-2, the virus’ spike protein binds to the ACE2 receptor in our cells to infect us. If we can block that receptor, the virus cannot enter. Through computer modeling, we found that defensins can bind to both the ACE2 receptor and the spike protein so that the virus cannot enter.”

The implications of this discovery are wide-reaching. A supplement or drug enhanced with defensins could potentially bolster an immune system’s ability to ward off viral or bacterial invaders before they take hold.

While new drug development often takes decades, this discovery sets the stage for targeted protein engineering and future clinical research — early steps toward developing novel antivirals or antibiotics.

“When we made this discovery, I got super excited about what implications this might have in the future,” Baindara said. “Hopefully other scientists and drug developers can benefit from this work so that we can one day see new antivirals or antibiotics involving defensins.”

Mizzou’s pursuit is far from finished. The microbial world remains largely uncharted. Less than 1% of the world’s many microbes — tiny living organisms too small to be seen with the naked eye — have been identified by scientists, fueling their curiosity.

“Microbes are all around us — in the air, in the soil, on our hands and skin — and they continue to evolve,” Baindara said. “So, the quest to find better targets for antivirals and antibiotics is ongoing, and we’re proud to contribute to that search. Different viruses have different kinds of receptors, so going forward, we can see what else defensins might be able to help protect against, whether that be influenza, respiratory syncytial virus or even bacterial infections such as tuberculosis.”

“Repurposing of human defensins as a promising antiviral therapeutics against SARS-CoV-2,” was published in The Microbe.