For decades, cardiovascular medicine has approached high cholesterol from one direction: catching the problem after the cholesterol-carrying particles have already been built. Statins, the most widely prescribed cholesterol medications in the United States, work by blocking an enzyme involved in cholesterol production inside cells. Newer drugs like PCSK9 inhibitors work by helping the body clear LDL cholesterol from the bloodstream after it has been released. Both approaches succeed by intercepting the cholesterol pipeline somewhere along its existing route.
A study published in the American Heart Association journal Circulation has identified a different point of intervention. UT Southwestern Medical Center researchers found that a protein called HELZ2 controls cholesterol production at an earlier stage than any major existing therapy targets. HELZ2 works by destroying the genetic instructions that tell liver cells to build apoB, the foundational protein that carries cholesterol through the bloodstream. The finding, widely reported in late May 2026 following its original publication, opens the door to a new category of cardiovascular drugs that could fundamentally shift how the United States treats the condition affecting nearly 38% of American adults.
The shift is not theoretical. The biological mechanism HELZ2 controls has been validated in mice, the protein has been mapped in detail, and the gain-of-function mutation that increases HELZ2 activity produced measurable reductions in atherosclerotic plaque buildup in animal models. Translating that into a human therapeutic will take years. But the path is now visible in a way it was not before.
What HELZ2 Actually Does
Cholesterol does not travel through the bloodstream on its own. It is carried by particles called lipoproteins, which are built around a structural protein called apoB. Without apoB, the liver cannot assemble and release the LDL particles that deliver cholesterol throughout the body. When LDL levels rise too high, the particles can deposit cholesterol in artery walls, leading to the plaque buildup that drives heart attacks and strokes.
Most existing cholesterol therapies work somewhere downstream of apoB production. Statins reduce the raw material the liver uses to make cholesterol. PCSK9 inhibitors help clear LDL from the bloodstream after it has been released. Newer therapies like inclisiran target the genetic machinery that produces PCSK9. Each approach has reduced cardiovascular events in clinical trials, and the combination of statins, ezetimibe, and PCSK9 inhibitors has become the standard of care for high-risk patients.
HELZ2 operates at a step earlier than any of these. The protein controls the lifespan of the messenger RNA (mRNA) that carries the genetic instructions for apoB. When HELZ2 activity increases, the apoB mRNA breaks down faster, fewer apoB proteins are produced, and fewer lipoproteins are assembled and released into the bloodstream. The result is lower LDL levels and reduced plaque buildup.
Senior author Zhao Zhang, Ph.D., Assistant Professor in UT Southwestern’s Center for the Genetics of Host Defense and of Internal Medicine, described the mechanism as a powerful control point. Co-author Yiao Jiang, Ph.D., a postdoctoral researcher in the Zhang Lab, emphasized why the finding surprised the team: “Most previous research focused on what happens to apoB after it’s already made. What surprised us is that HELZ2 acts much earlier, by controlling how long the apoB ‘message’ survives before the protein is even produced.”
Why “Earlier” Matters in Drug Development
In pharmacology, intervening earlier in a biological pathway often produces more durable effects and fewer side effects than intervening downstream. Downstream interventions tend to require continuous drug presence to maintain their effect, because the underlying production machinery keeps running. Upstream interventions can shift the entire pathway by adjusting how much raw material flows through it.
The HELZ2 mechanism is upstream of every existing cholesterol therapy. By reducing how much apoB the liver produces in the first place, HELZ2 effectively dials down the entire LDL production pipeline at its source. The downstream effects of every other intervention would compound on top of this baseline reduction.
This has implications for both new drug development and combination therapy. A HELZ2-targeting drug, if developed, would not replace statins or PCSK9 inhibitors. It would potentially complement them, allowing physicians to attack high cholesterol from multiple angles simultaneously. For patients with familial hypercholesterolemia, statin-resistant high cholesterol, or aggressive plaque progression, the addition of an upstream therapy could be transformative.
What the Research Has Established So Far
The study used a large-scale genetic screening system developed by Nobel Laureate Bruce Beutler, M.D., Director of the Center for the Genetics of Host Defense at UT Southwestern. Beutler shared the 2011 Nobel Prize in Physiology or Medicine for his discovery of an important family of immune cell receptors. The screening system allowed the team to identify mice with unusual liver fat accumulation patterns and trace the cause back to a specific mutation in HELZ2.
The mutation the team identified is a gain-of-function variant, meaning it makes HELZ2 more active than its normal form. Mice with the mutation produced less apoB protein, fewer lipoproteins, and lower blood LDL and triglyceride levels. In mice that lacked the LDL receptor (a model used to study atherosclerosis), the HELZ2 mutation reduced atherosclerotic plaque buildup compared to controls. The aortic root images comparing the two groups, included in the publication, showed visibly less plaque in the HELZ2 mutation group.
The study also identified a tradeoff. Mice with heightened HELZ2 activity showed lower blood LDL but increased liver fat. This is important because fatty liver disease is itself a major cardiovascular and metabolic risk factor in humans. Any future therapy targeting HELZ2 will need to balance the cholesterol benefit against the potential for liver fat accumulation.
The full study citation is Jiang, Y., et al. (2025), “HELZ2 Regulates ApoB mRNA Stability to Modulate Fatty Liver Disease and Atherosclerosis,” Circulation. DOI: 10.1161/circulationaha.125.076468.
The American Cholesterol Problem
High cholesterol affects roughly 38% of American adults according to CDC data, or approximately 94 million people aged 20 and older. The condition is one of the largest modifiable risk factors for cardiovascular disease, which remains the leading cause of death in the United States. Existing therapies have made substantial progress against the problem, but a meaningful share of Americans either cannot tolerate statins, do not achieve target LDL levels on existing medication regimens, or have genetic forms of high cholesterol that resist standard treatment.
The statin market alone exceeds $15 billion globally, and PCSK9 inhibitors generate billions more despite their high cost. Any new cholesterol therapy that demonstrates safety and efficacy enters a market with sustained demand and proven willingness to pay. For pharmaceutical companies, that economic backdrop makes upstream cholesterol mechanisms an active area of investment.
For patients, the practical question is when. Drug development timelines from initial mechanism discovery to FDA approval typically run 10 to 15 years. Even in a relatively favorable scenario, a HELZ2-targeting therapy would likely not reach U.S. patients before the mid-2030s. The path between mouse studies and human treatments includes safety testing, mechanism validation in humans, dosing studies, and large-scale clinical trials.
What Comes Next for HELZ2 Research
The immediate next steps for the UT Southwestern team and the broader cardiovascular research community will involve validating the HELZ2 mechanism in human cell models, understanding how human genetic variation affects HELZ2 activity, and identifying potential small-molecule or RNA-based approaches that could safely increase HELZ2 activity in patients.
The liver fat tradeoff observed in the mouse models will be a critical research priority. If increased HELZ2 activity reliably produces fatty liver disease as a side effect, the therapeutic window for any HELZ2-targeting drug will be narrow. If the tradeoff can be managed through careful dosing or combination with other liver-protective agents, the path forward becomes more viable.
The genetic screening approach developed by Beutler’s lab has been productive for cardiovascular research, and HELZ2 is unlikely to be the last cholesterol-related target it identifies. The broader implication is that the cardiovascular medicine pipeline is shifting from incremental improvements on existing drug classes to fundamentally new mechanisms identified through systematic genetic screening.
The Bigger Picture for Cardiovascular Medicine
For the past 30 years, the dominant story in cholesterol treatment has been statins. Statins reduced cardiovascular mortality at population scale, became one of the most prescribed drug classes in U.S. medicine, and remained the foundation of high-cholesterol treatment despite the emergence of newer therapies. The next 30 years may look different.
HELZ2 represents one of several emerging mechanisms that target cholesterol production rather than cholesterol clearance. Other research has explored RNA-based therapies, gene editing approaches, and protein interactions that occur even earlier in the cholesterol pipeline. The convergence of these approaches suggests cardiovascular medicine is entering a phase where physicians will have multiple mechanistic tools to choose from rather than relying on statins as the universal first-line treatment.
For the 94 million Americans currently affected by high cholesterol, the practical impact of the HELZ2 discovery will arrive slowly. The patients who will benefit most directly are likely children and young adults today who will be diagnosed with high cholesterol in the 2030s and 2040s, when HELZ2-based therapies may have moved through development and approval. The patients currently managing high cholesterol with statins and PCSK9 inhibitors will continue to depend on those established treatments for the foreseeable future.
The longer-term promise is significant. A cholesterol therapy that intervenes before apoB is even produced represents a fundamentally different approach to cardiovascular prevention than anything currently available. The UT Southwestern team has identified the switch. The years of work between this finding and the first prescription written for a HELZ2-targeting drug will determine how much it ultimately matters.
For now, the discovery joins a growing body of cardiovascular research suggesting that the genetic and molecular tools available to medicine are expanding faster than any single generation of therapies could capture. The next era of cholesterol treatment will not look like the statin era. HELZ2 is one of the early signals of what that next era could include.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. The research discussed has been conducted in mice and has not yet been validated in human clinical trials. No HELZ2-targeting therapy is currently available for patients, and the development timeline for any such therapy would span years. Readers should not change or discontinue any prescribed cholesterol medication based on this article. People with high cholesterol, cardiovascular disease, fatty liver disease, or related conditions should consult a qualified healthcare provider before making any decisions about treatment. Statins, PCSK9 inhibitors, and other approved cholesterol therapies have established safety and efficacy profiles that should not be replaced based on emerging research. Always seek the advice of a physician or other qualified healthcare provider with any questions regarding a medical condition.
