PAGER expertise unlocks new potential for controlling mobile exercise

A fundamental perform of cells is that they act in response to their environments. It is smart, then, {that a} objective of scientists is to regulate that course of, making cells reply how they wish to what they need.

One avenue for this ambition is cell receptors, which perform like ignition slots on a cell, requiring keys – similar to particular hormones, medication, or antigens – to begin up particular mobile actions. There are already artificial receptors that give us some management over this sequence of occasions, most famously the chimeric antigen receptors utilized in CAR-T cell most cancers remedy. However present artificial receptors are restricted within the number of keys they’ll settle for and the actions they’ll set off.

Now, detailed in a paper printed Dec. 4 in Nature, Stanford researchers have developed a brand new artificial receptor that accommodates a broader vary of inputs and produces a extra various set of outputs.

This innovation, referred to as “Programmable Antigen-gated G protein-coupled Engineered Receptors” (PAGER), is constructed round G protein-coupled receptors, a set of over 800 proteins within the human physique that activate molecular switches contained in the cell, referred to as G-proteins, to regulate many very important capabilities. The researchers demonstrated PAGER’s versatility by efficiently controlling neuronal exercise, triggering immune responses, and delivering therapeutic remedies in lab experiments.

I feel PAGER has potential for influence, each within the G protein coupled receptor biology subject, and in artificial circuits or cell-based therapies. Once you put a expertise on the market, it is at all times thrilling to see all of the inventive ways in which folks use and remodel the expertise in ways in which you by no means even imagined. There’s a lot extra that is doable.”

Alice Ting, professor of genetics on the Faculty of Drugs and of biology within the Faculty of Humanities and Sciences and senior creator of the paper

Holding the keys

Whereas G-protein coupled receptors can activate numerous mobile actions, researchers had beforehand prevented them for programmable purposes as a result of customizing their “keys” was difficult, actually requiring researchers to direct the evolution of the receptors for years to create only one desired choice.

“G-protein coupled receptors, usually, could be activated by particular small molecules that bind in a pocket within the receptor,” defined Nicholas Kalogriopoulos, a postdoctoral fellow within the Ting lab and co-lead creator of the paper. “Basically, what we did is fuse one thing that blocks that pocket, and it solely opens up when it binds one thing you have chosen.”

In different phrases, the researchers added a layer of safety – a nanobody coupled with a peptide antagonist – that guards the ignition. Like a automobile’s proprietor contemplating whether or not to lend it to a buddy, the nanobody and peptide antagonist solely permit for insertion of the important thing underneath particular circumstances. This configuration not solely limits entry to the receptor but in addition makes it doable to swap out the “proprietor” to vary the entry standards. This modularity, mixed with the plentiful affect of G-proteins, means PAGER may allow an unimaginable range of cell responses.

All of it works

To place PAGER via its paces, the researchers partnered with Ivan Soltesz, the James R. Doty Professor in Neurosurgery and Neurosciences at Stanford Drugs, and Yulong Li, the Boya Professor at Peking College, who’re each co-authors of the paper.

“The very collaborative setting of Stanford expedited the research. I feel it actually led to the success of the experiment and the undertaking,” mentioned Reika Tei, a postdoctoral fellow within the Ting lab and co-lead creator of the paper.

In lab experiments, the researchers used PAGER to change neuronal exercise in a cell tradition and a piece of mouse mind, management T-cell migration, change the inflammatory state of macrophages (a sort of immune cell), and secrete therapeutic antibodies in response to the presence of tumor antigens.

“We did not count on all 4 purposes to work instantly, however they did, which made me really feel actually good in regards to the expertise,” mentioned Ting. “We did not have any utility the place we tried it and it did not work – which isn’t a promise to everybody that it will work for them – nevertheless it was sturdy.”

The subsequent steps for PAGER contain exploring totally different purposes, simplifying its construction, and enhancing its capability to function autonomously – similar to routinely delivering medication upon receptor binding. Though nonetheless in early phases, the researchers are assured in PAGER’s potential, particularly as different labs start to experiment with it.

“We have made PAGER simply programmable, and we might love to use it to all types of locations, however we do not have the experience for that,” mentioned Kalogriopoulos. “We’d like individuals who truly research the biology of a particular illness or mobile perform as a result of they know the correct inputs and outputs. So I am actually excited for folks to take it and begin utilizing it.”