Scientists block enzyme that drives fat production in mice

Obesity now kills more people than smoking did a generation ago. Heart disease, fatty liver, diabetes—the cascade of related illnesses costs health systems billions and cuts lives short. Yet for decades, weight management has relied on the same basic tools: willpower, diet, exercise, and a handful of drugs that work inconsistently or come with side effects people would rather avoid.

Now researchers at University Hospitals and Case Western Reserve University have identified a previously unknown enzyme that might offer a different path forward.

The breakthrough centers on nitric oxide, a simple gas molecule that acts like a chemical messenger inside your cells. Think of it as a dimmer switch for metabolism—when it attaches to the right proteins, it tells your body to slow down fat production. But an enzyme called SCoR2 acts like an eraser, removing nitric oxide from those proteins and essentially flipping the switch back on. More SCoR2 activity means more fat synthesis, more cholesterol production, more metabolic trouble.

In a study published in Science Signaling, the team blocked SCoR2 using both genetic techniques and a newly developed drug. In mice, the approach worked. Animals on the drug didn't gain weight the way untreated mice did. Their cholesterol dropped. Their livers—often damaged by excess fat—showed improvement.

"We have a new class of drug that prevents weight gain and lowers cholesterol," explained Jonathan Stamler, the study's lead author. "A potential therapy for obesity and cardiovascular disease, with additional hepatic benefits."

What makes this different from other obesity drugs isn't just the mechanism—it's the specificity. Rather than blunting appetite or speeding metabolism broadly, this approach targets the exact molecular switch that tells fat cells to multiply. In the liver, blocking SCoR2 stops fat and cholesterol synthesis directly. In fat tissue itself, it silences the genetic instructions that create the enzymes needed for fat production.

The work is early. These are mouse studies, and the gap between rodent metabolism and human biology is real. But the researchers have already moved beyond proof-of-concept—they've developed an actual drug compound that works, not just a theoretical target. Clinical trials in humans should begin within about 18 months.

For the millions of people who've tried every diet and struggled with existing medications, that timeline matters. A genuinely new mechanism, tested and ready for human study, shifts obesity from "manage it forever" territory into "potentially treatable condition" territory. It won't be a magic pill—no drug ever is. But it might be the opening that changes how we approach one of the most intractable health challenges of our time.