Like brain cells, kidney cells can ‘remember’

Kidney cells can also form memories. At least in a metaphorical sense.

Neurons have historically been the cell most closely associated with memory. But far outside the brain, kidney cells can also store information and recognize patterns in a way similar to neurons, researchers report Nov. 7 in Nature Communications.

“We’re not saying that this kind of memory helps you learn trigonometry or remember how to ride a bicycle or preserve childhood memories,” says Nikolay Kukushkin, a neuroscientist at New York University. “This research adds to the idea of ​​memory; does not challenge existing concepts of memory in the brain.”

In experiments, kidney cells showed signs of what is called the “space-to-mass effect.” This well-known feature of how memory works in the brain makes it easier to store information in small chunks over time, rather than a large chunk at once.

Outside the brain, cells of all kinds need to keep track of things. One way to do this is through a protein central to memory processing, called CREB. It, and other molecular components of memory, are found in neurons and non-neuronal cells. While cells have similar parts, researchers weren’t sure if the parts worked the same way.

In neurons, when a chemical signal passes through, the cell starts producing CREB. The protein then activates more genes that further change the cell, turning on the molecular memory machine (SN: 2/3/04). Kukushkin and colleagues set out to determine whether CREB in non-neuronal cells responds to input signals in the same way.

Researchers inserted an artificial gene into human embryonic kidney cells. This artificial gene largely matches the naturally occurring stretch of DNA that CREB activates by binding to it—a region researchers call a memory gene. The inserted gene also included instructions for producing a glowing protein found in fireflies.

The team then observed the cells responding to artificial chemical impulses that mimic the signals that trigger the memory machinery in neurons. “Depending on the light [the glowing protein] produces, we know how strongly that memory gene is activated,” says Kukushkin.

Different timing patterns of the pulses resulted in different responses. When the researchers applied four three-minute chemical pulses separated by 10 minutes, the light 24 hours later was stronger than in cells where the researchers applied a “massive” pulse, a single 12-minute pulse.

“This [massed-spaced] The effect has never been seen outside the brain, it’s always been thought of as this property of neurons, of a brain, how memory is formed,” says Kukushkin. “But we propose that maybe if you give non-brain cells complex enough tasks, they will also be able to form a memory.”

Neuroscientist Ashok Hegde calls the study “interesting because they are applying what is generally considered a principle of neuroscience somewhat broadly to understanding gene expression in non-neuronal cells.” But it’s unclear how generalizable the findings are to other cell types, says Hegde, of Georgia College & State University in Milledgeville. However, he says this research could one day help in the search for potential drugs to treat human diseases, especially those where memory loss occurs.

Kukushkin agrees. The body can store information, he says, and this can be significant for one’s health.

“Maybe we can think of cancer cells as having memories and think about what they can learn from the chemotherapy model,” says Kukushkin. “Maybe we need to consider not just how much drug we’re giving a person, but what the temporal pattern of that drug is as we think about how to learn more efficiently.”