Gram Research analysis of a 2026 study in Atherosclerosis found that removing the JARID2 protein from immune cells in mice modestly raised blood cholesterol and triglycerides and increased fat-filled foam cells, but did not change artery plaque size. The results come from a mouse study that cannot yet show effects in people.
A new study in the journal Atherosclerosis looked at a protein called JARID2 in the immune cells that build up artery plaque. Gram Research analysis of this work found that when mice lacked JARID2 in these immune cells, their blood had slightly more cholesterol and triglycerides, and more fat-filled cells formed in their artery walls. Surprisingly, the size and makeup of the artery plaque did not change after nine weeks on a high-cholesterol diet. The researchers also found higher levels of JARID2 in unstable plaques from human arteries, which suggests the protein may matter for plaque stability. Because this work was done in mice, it cannot yet show what happens in people. It does point to a complicated system in which opposing effects appear to balance each other out.
Key Statistics
A 2026 mouse study published in Atherosclerosis found that removing the JARID2 protein from immune cells modestly raised blood cholesterol and triglycerides but did not change artery plaque size after nine weeks on a high-cholesterol diet.
A 2026 study in Atherosclerosis reported that JARID2 levels were higher in unstable human artery plaques, suggesting the protein may be linked to plaque instability.
The Quick Take
- What they studied: Scientists wanted to know whether a protein called JARID2, which controls how genes are switched on and off, affects how artery plaque forms in immune cells.
- Who participated: The main experiments used laboratory mice that were genetically altered so their immune cells lacked JARID2, compared with normal mice. The exact number of mice was not listed in the study summary. Human artery plaque samples were also examined.
- Key finding: Mice without JARID2 in their immune cells had modestly higher blood cholesterol and triglycerides and formed more fat-filled cells in their artery walls. However, the overall size of their artery plaques did not change.
- What it means for you: This study does not offer any change you can make today. It is an early step in understanding how immune cells, fats, and artery disease connect. Anyone concerned about heart health should keep following proven steps like eating well, staying active, and talking with a doctor about cholesterol.
The Research Details
The researchers bred mice that could not make JARID2 in their myeloid immune cells, a group of white blood cells that includes macrophages. Macrophages are immune cells that soak up fat and play a central role in artery plaque. Bone marrow, the tissue that produces blood cells, was taken from these mice and from normal mice, then transplanted into mice that are prone to developing high cholesterol and artery disease.
After the transplant, all the mice ate a high-cholesterol diet for nine weeks to encourage plaque to form. The team then measured blood fats, counted fat-filled immune cells in the artery walls, measured plaque size and composition, and used a method called single-cell RNA sequencing. This technique reads the activity of genes inside individual cells, which allowed the team to see how different immune cell types behaved in the plaques.
The team also looked at human artery plaque samples and found that JARID2 was higher in plaques that were unstable, meaning more likely to rupture. Using both mouse experiments and human tissue helps connect laboratory findings to real disease, although the two approaches cannot fully substitute for each other.
Using a mouse model that is prone to artery disease lets scientists control the genes of specific immune cells and track what happens over time. Transplanting only the immune cells, rather than changing the whole animal, helps show that the effect comes from the immune system itself. Single-cell reading is useful because plaques contain many different cell types that can act in opposite ways, and averaging them together could hide important details.
The study combines several methods, including blood tests, tissue analysis, and gene reading in individual cells, which makes the findings more convincing than a single measurement would be. The use of both mice and human tissue is also a strength. However, the summary does not list the number of mice per group, and results from mice do not always carry over to people. Readers should treat the findings as early evidence that needs confirmation in larger and longer studies.
What the Results Show
The clearest result was that mice lacking JARID2 in their immune cells had modestly higher levels of cholesterol and triglycerides in their blood. Triglycerides are a type of fat that circulates in the blood, and high levels are linked to heart disease in people. The word modestly is important here, because the increase was small rather than dramatic.
These same mice also formed more foam cells. Foam cells are immune cells that have become packed with fat and are a key early step in artery plaque. Seeing more of them suggests that losing JARID2 makes immune cells more likely to take up fat from the blood.
Despite these changes, the size and makeup of the artery plaques were not different from those in normal mice. This is the surprising part of the study. The authors suggest that opposing effects may cancel each other out, so the higher blood fats are balanced by other changes in the immune cells.
The single-cell analysis supported this idea. Losing JARID2 appeared to have both helpful and harmful effects, depending on the type of immune cell and the context. Together, these results suggest a complex balance rather than a simple harmful or helpful effect.
JARID2 was found at higher levels in unstable human artery plaques compared with more stable ones. This connection suggests the protein may influence whether a plaque stays calm or becomes dangerous, which is important because unstable plaques are more likely to cause heart attacks and strokes. However, a link between a protein and plaque instability does not prove that the protein causes instability.
The mixed inflammatory effects seen in single-cell data also matter. Inflammation is the body’s response to injury or stress, and in artery disease it can either help or harm. The study showed that JARID2 can push immune cells in different directions, which may explain why its overall effect on plaque size was neutral.
Previous research has shown that a related protein, EZH2, which works in the same protein group called PRC2, promotes artery disease in immune cells. This study looked at a partner of that complex and found that its effects are less straightforward. Together, the findings suggest that gene-controlling proteins in immune cells are an active area of research for heart disease, although more work is needed before any treatment is designed around them.
The main experiments were done in mice, which differ from people in diet, metabolism, and immune system details. The mice were also fed a high-cholesterol diet for only nine weeks, while human artery disease develops over many years. The summary does not state how many mice were used, which makes it harder to judge how strong the results are. Because the effects on plaque size were not seen, the study also cannot tell us whether JARID2 changes heart risk in people. Finally, the human tissue findings show an association, not proof that JARID2 causes plaque instability.
The Bottom Line
Based on this single mouse study, there are no practical recommendations for changing care. Confidence that JARID2 directly affects human artery disease is low at this stage. The findings are best viewed as a useful clue for future research. Proven steps for heart health, such as eating fewer saturated fats, staying active, not smoking, and taking prescribed cholesterol medicines, remain well supported by much larger bodies of evidence.
Researchers studying heart disease, immune cells, and gene control will likely find this study especially relevant. People with heart disease or high cholesterol should not change their treatment based on this work. Anyone interested in future treatments may want to follow newer studies, but should talk with a doctor before making decisions about medicines or supplements.
Findings from mouse studies typically take years to test in people, and many early ideas never become treatments. Any real-world application of research on JARID2 would likely need several rounds of laboratory work, animal studies, and human clinical trials. For readers today, the realistic expectation is simply to stay with well-established heart health habits while the science develops.
Frequently Asked Questions
What did the JARID2 study in Atherosclerosis find?
Mice lacking JARID2 in their immune cells had modestly higher blood cholesterol and triglycerides and formed more fat-filled foam cells. Their artery plaque size stayed the same after nine weeks on a high-cholesterol diet, suggesting opposing effects may balance out.
Does JARID2 cause heart disease in humans?
This study does not prove that JARID2 causes heart disease in humans. It was done mainly in mice, and it found that JARID2 was higher in unstable human artery plaques, which is an association. Larger human studies would be needed to confirm any role.
Can I change my diet based on the JARID2 research?
No changes are supported by this study alone. Proven heart-health steps include eating fewer saturated fats, staying physically active, avoiding smoking, and following your doctor’s cholesterol plan. Talk with a healthcare provider before making any major dietary or medication changes.
What is a foam cell and why does it matter for artery health?
A foam cell is an immune cell that has absorbed large amounts of fat and looks foamy under a microscope. Foam cells are an early step in artery plaque formation, so finding more of them in the study suggests the immune cells were taking up more fat from the blood.
Want to Apply This Research?
- Track your weekly saturated fat intake in grams and your weekly minutes of moderate activity, aiming to log at least 150 minutes per week. If you have had a recent lipid panel, record your total cholesterol, triglycerides, and LDL cholesterol values with the test date, and update them after each check-up.
- Use the app to set one small, realistic goal, such as swapping one fried meal per week for baked or grilled food, or adding a 20-minute walk on three days each week. Review your progress every Sunday and adjust the goal if it feels too easy or too hard.
- Build a long-term log that combines diet, activity, and periodic blood test results so you can see trends over six to twelve months. Share these summaries with your doctor during visits, and treat any sudden changes in blood fats as a reason to seek medical advice rather than a reason to change treatment on your own.
This article summarizes a laboratory study conducted mainly in mice and is intended for general education only. The findings have not been confirmed in people and should not be used to make decisions about diet, medication, or treatment. Consult a qualified healthcare provider before making any changes related to heart health or cholesterol.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.