Researchers discovered that two kidney proteins called PHD2 and PHD3 control whether special kidney cells produce renin (which regulates blood pressure) or EPO (which makes red blood cells). According to Gram Research analysis, when these proteins were removed in laboratory mice, cells switched from producing renin to producing EPO when blood pressure dropped, and this switch was reversible. This finding reveals how the body flexibly adjusts hormone production based on what it needs.
Scientists discovered how special cells in your kidneys decide whether to make renin (a hormone that controls blood pressure) or erythropoietin (a hormone that makes red blood cells). According to Gram Research analysis, the study found that two proteins called PHD2 and PHD3 act like switches that control what these kidney cells produce. When researchers removed these proteins in mice, the cells switched from making renin to making EPO instead, especially when blood pressure dropped. This discovery could help explain how the body adapts to different conditions and might lead to new treatments for anemia and blood pressure problems.
Key Statistics
A 2026 research study in The Journal of Physiology found that removing PHD2 and PHD3 proteins in mouse kidney cells caused them to switch from producing renin to producing erythropoietin when blood pressure was lowered through diet and medication.
The study demonstrated that kidney cell transformation from renin-producing to EPO-producing cells was reversible despite permanent genetic changes, showing that cells retain flexibility in their hormone-producing functions.
Research revealed that HIF-2α stabilization alone was insufficient to trigger EPO production in preglomerular kidney cells; additional signals from the body’s physiological state were required for the hormone switch to occur.
The Quick Take
- What they studied: How two kidney proteins (PHD2 and PHD3) control whether special kidney cells make renin (blood pressure hormone) or EPO (red blood cell hormone)
- Who participated: Laboratory mice with genetically modified kidney cells, studied under normal conditions and after treatments that lowered blood pressure
- Key finding: When PHD2 and PHD3 proteins were removed, kidney cells switched from producing renin to producing EPO, especially when blood pressure dropped
- What it means for you: This research helps scientists understand how the body naturally adjusts hormone production based on what it needs, which could lead to better treatments for anemia and blood pressure disorders. However, this is early-stage research in mice, not yet tested in humans
The Research Details
Researchers created special laboratory mice where they could turn off the PHD2 and PHD3 genes specifically in kidney muscle cells. They then observed what happened to these cells under two conditions: normal baseline conditions and after treatment with a low-salt diet combined with a blood pressure medication (enalapril) that stimulates renin production. By comparing normal mice to mice missing one or both proteins, scientists could see exactly what role these proteins play in controlling hormone production.
The study examined kidney tissue samples and measured which hormones the cells were producing using molecular biology techniques. This allowed researchers to track not just what hormones were made, but also the genetic instructions (gene expression) that told cells what to produce. They could see the actual shift in cellular programming that occurred when the proteins were removed.
Understanding how kidney cells switch between different hormone-producing functions is important because it reveals how the body adapts to challenges like low blood pressure or low oxygen. If scientists can understand these switches, they might be able to control them to treat diseases where the body isn’t making enough of these critical hormones.
This is a controlled laboratory study using genetically modified mice, which allows researchers to isolate the exact effect of removing these proteins. The findings are based on direct observation of kidney tissue and molecular measurements, making the results reliable for understanding basic biology. However, mouse studies don’t always translate directly to humans, so these findings need further research before they could become medical treatments.
What the Results Show
The most important discovery was that removing PHD2 and PHD3 proteins changed what kidney cells produced. Under normal conditions, removing these proteins didn’t immediately cause cells to make EPO—they still looked and acted like normal kidney cells. However, when blood pressure was lowered through diet and medication, something remarkable happened: the cells switched from making renin to making EPO instead.
The researchers found that this switch was reversible. Even though the genetic changes that stabilized HIF-2α (a key protein that controls oxygen-sensing) remained in place, the cells could still switch back and forth between making different hormones depending on the body’s needs. This suggests the cells retain their flexibility and aren’t locked into one function.
Interestingly, the effect was different in different types of kidney cells. In the main cells studied (preglomerular VSMCs), the switch happened when blood pressure dropped. But in other kidney cells called interstitial pericytes, the switch to EPO production happened regardless of blood pressure changes, just from removing the PHD proteins.
The study revealed that HIF-2α stabilization alone wasn’t enough to trigger EPO production—the cells needed additional signals from the body’s condition (like low blood pressure). This shows that hormone production is controlled by multiple factors working together, not just one switch. The research also showed that the cells underwent a complete change in their genetic programming, shifting from a ‘renin-cell-like’ pattern to an ‘EPO-cell-like’ pattern, demonstrating true cellular transformation rather than just temporary changes.
Previous research had shown that renin-producing cells could transform into EPO-producing cells when HIF-2α was stabilized. This study extends that finding by showing the reverse is also possible—that contractile muscle cells can transform into EPO producers. It also reveals that the transformation is more nuanced than previously thought, requiring both genetic changes and appropriate body signals to occur.
The study was conducted entirely in laboratory mice, so results may not directly apply to humans. The sample size of mice used wasn’t specified in the abstract. The research focused on specific kidney cells and may not explain how the entire kidney system responds to these changes. Additionally, the study examined relatively short-term changes, so it’s unclear how these transformations would affect the body over longer periods.
The Bottom Line
This research is fundamental science that helps explain how the body works—it’s not yet at the stage of recommending specific treatments. However, it suggests that future therapies might be able to control these kidney cell switches to treat anemia (by increasing EPO production) or blood pressure problems (by controlling renin production). Anyone with anemia or blood pressure disorders should continue following their doctor’s current treatment plans while scientists develop new approaches based on this research.
This research is most relevant to people with anemia, chronic kidney disease, or blood pressure disorders, as well as researchers developing new treatments for these conditions. It’s less immediately relevant to people with healthy kidney function, though the basic biology applies to everyone.
This is early-stage research. Even if it leads to new treatments, it typically takes 10-15 years for basic research discoveries to become available medications. Current treatments should remain the standard of care.
Frequently Asked Questions
What controls whether kidney cells make renin or EPO?
Two proteins called PHD2 and PHD3 act as switches. When these proteins are removed, kidney cells can switch from making renin (blood pressure hormone) to making EPO (red blood cell hormone), especially when blood pressure drops. This switch is controlled by a protein called HIF-2α.
Can kidney cells change what hormones they produce?
Yes, according to 2026 research, kidney cells can reversibly switch between producing different hormones. Even with permanent genetic changes, cells maintained flexibility to produce either renin or EPO depending on the body’s needs and blood pressure levels.
How might this research help treat anemia?
Understanding how to control the switch that makes kidney cells produce EPO could lead to new anemia treatments. Instead of injecting EPO, doctors might eventually trigger the body’s own kidney cells to produce more EPO naturally by manipulating these protein switches.
Does this research apply to humans yet?
This is early-stage research conducted in laboratory mice. While it reveals important biology, it hasn’t been tested in humans yet. Current anemia and blood pressure treatments remain the standard of care. New human treatments based on this discovery are likely years away.
What is HIF-2α and why does it matter?
HIF-2α is a protein that senses oxygen levels and controls gene activity in kidney cells. Stabilizing HIF-2α (keeping it active) helps determine whether cells produce EPO or renin, making it a key control point for kidney hormone production.
Want to Apply This Research?
- Users with anemia or blood pressure concerns could track hemoglobin levels (red blood cell count) and blood pressure readings over time to monitor their condition and see how treatments affect these key markers
- While this research doesn’t yet suggest specific lifestyle changes, users could use an app to monitor factors that affect kidney health: blood pressure, salt intake, hydration, and medication adherence—all of which relate to the renin-EPO system this research describes
- Long-term tracking of blood pressure and anemia symptoms (fatigue, shortness of breath) would help users and doctors understand their kidney hormone system’s function and how well treatments are working
This research describes basic kidney biology in laboratory mice and has not been tested in humans. It does not constitute medical advice. Anyone with anemia, kidney disease, or blood pressure disorders should continue following their healthcare provider’s treatment recommendations. This research is early-stage and may not lead to clinical applications for many years. Do not attempt to self-treat based on this information.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.