Your kidneys filter 180 litres of blood every single day. They handle toxic waste, regulate electrolytes, and manage fluid balance. But when kidney cells die through a process called ferroptosis, they don’t go quietly. Iron accumulates inside them, triggering a chain reaction that generates toxic compounds and destroys the cell from within. Now researchers are finding that a cellular defence system called the NRF2 pathway can throw a switch to stop this iron-driven death before it starts.
What is ferroptosis
Ferroptosis is a form of cell death that looks nothing like apoptosis, the neat, orderly programme cells usually run when they need to die. Instead, ferroptosis is messy and chaotic. Iron accumulates inside the cell and reacts with hydrogen peroxide, creating free radicals through a process called the Fenton reaction. These radicals tear through cell membranes, lipids oxidise, and the cell ruptures.
The process was only formally named about a decade ago, but scientists recognised something different was happening in cells exposed to certain poisons or stressed by injury. Unlike apoptosis, ferroptosis doesn’t rely on the usual death machinery. It’s driven by iron chemistry and lipid peroxidation. That makes it a much harder target to hit with drugs, because it operates through fundamentally different mechanisms than what researchers had learned to interrupt.
In kidney disease, ferroptosis appears to be a major culprit. Kidney cells, especially those in the proximal tubule responsible for reabsorbing nutrients and water, are loaded with iron. They’re also exposed to reactive oxygen species as part of their normal work. When stress accumulates, that iron becomes a liability rather than a tool.
What the research shows
Studies examining kidney injury in animal models and cultured kidney cells reveal that when NRF2 activates, it launches a coordinated defensive strategy against ferroptosis. NRF2 is a transcription factor, meaning it travels to the nucleus and switches on specific genes. When kidney cells face oxidative stress, NRF2 doesn’t just flip one switch. It flips dozens.
One critical gene NRF2 activates codes for a protein called GPX4. This protein neutralises lipid peroxides before they damage the cell membrane. Another set of genes controlled by NRF2 produce proteins that manage iron storage, keeping it locked away in ferritin where it can’t participate in the Fenton reaction. A third group of NRF2-controlled genes boost the cell’s production of glutathione, a master antioxidant that mops up free radicals.
When researchers deliberately activated NRF2 in kidney cells under stress, those cells survived ferroptotic conditions that killed untreated neighbours. When they blocked NRF2 signalling, cells became far more vulnerable to ferroptosis. The pathway isn’t just involved. It’s fundamental to ferroptosis resistance.
In kidney disease models, tissues with higher NRF2 activity show less ferroptosis-related damage. That protection appears to slow the progression of kidney dysfunction. This observation has generated genuine interest because existing kidney disease treatments mainly slow disease progression rather than reversing it.
Why cells need this
Ferroptosis seems like a catastrophic failure of cellular maintenance. Why would evolution preserve any mechanism related to it? The answer is that ferroptosis probably served an important purpose before humans lived long enough to develop chronic kidney disease.
In normal tissues, ferroptosis acts as a fail-safe mechanism. If a cell becomes cancerous or dangerously infected, triggering ferroptosis instead of letting it survive might prevent tumours or spread pathogens. Some cancer cells actually rely on blocking ferroptosis to survive. That’s why researchers are exploring ferroptosis induction as a cancer treatment strategy.
The NRF2 pathway, on the other hand, evolved to keep cells alive under stress. Oxidative stress is constant in living systems. Cells generate reactive oxygen species during energy production, immune responses, and inflammation. NRF2 represents billions of years of evolutionary refinement for surviving in that hostile biochemical environment. In young, healthy tissues, this system works beautifully. In ageing kidneys under chronic stress, the same system becomes insufficient.
What affects the NRF2 pathway
NRF2 signalling isn’t a constant state. It fluctuates based on cellular conditions and external factors. Oxidative stress turns it on. Antioxidant defences turning it off again keeps cells from wasting energy on unnecessary defence signalling.
Age significantly impacts NRF2 function. Older animals show reduced NRF2 activation in response to the same stressors that powerfully activate it in young animals. The signalling pathway still exists, but it becomes sluggish. This decline correlates with increased ferroptosis vulnerability in kidney tissue.
Certain environmental factors enhance NRF2 signalling. Compounds like sulforaphane from cruciferous vegetables and polyphenols from various plants activate NRF2 through indirect mechanisms. Physical activity, caloric restriction, and temperature stress also increase NRF2 signalling in some tissues. Conversely, chronic inflammation, persistent oxidative stress from pollution exposure, and some medications can actually suppress NRF2 responsiveness over time.
Genetic background matters too. People inherit variations in NRF2 and related genes that influence how robustly this pathway activates. Some variations confer stronger ferroptosis resistance, while others leave cells more vulnerable. These genetic differences might explain why some individuals develop kidney disease more readily than others under similar environmental conditions.
What remains unknown
Researchers still can’t fully predict when NRF2 activation will help versus harm. In some cancers, excessive NRF2 signalling actually allows tumour cells to survive chemotherapy. This creates a therapeutic dilemma: boosting NRF2 to protect kidney cells might inadvertently help kidney cancer cells resist treatment. That’s not merely academic.
The relationship between NRF2 and the immune system in kidney disease remains poorly understood. NRF2 signalling in immune cells affects inflammation, which can either worsen or improve kidney outcomes depending on context. Scientists don’t yet know how to manipulate this balance selectively.
It’s also unclear how much ferroptosis actually contributes to human kidney disease progression versus other mechanisms. Most research uses animal models or isolated cells. Translating these findings to clinical settings requires understanding whether ferroptosis inhibition would meaningfully slow disease in actual patients, or whether other death pathways would simply compensate.
Finally, the possibility of long-term NRF2 activation carries unknown risks. Sustained high NRF2 signalling might impair normal cellular stress response mechanisms or create dependence on continuous activation. The research community hasn’t studied these questions systematically.
The NRF2 pathway represents one layer of an extraordinarily complex cellular defence system. Ferroptosis is just one of many ways kidney cells can be damaged in disease. Understanding how NRF2 prevents this specific form of iron-driven death illuminates the broader principle that cells possess multiple, overlapping survival strategies. Targeting one while ignoring others rarely produces the therapeutic outcomes researchers hope for. That’s the real challenge emerging from this research: not just understanding the biology, but figuring out how to translate it into meaningful clinical benefit.
Matt Elliott is the editor of Redox News Today, an independent publication covering peer-reviewed research on cellular health, redox signalling, and related biomedical science.
