PAGER expertise unlocks new potential for controlling mobile exercise

A primary perform of cells is that they act in response to their environments. It is smart, then, {that a} purpose of scientists is to manage 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 – corresponding to particular hormones, medicine, or antigens – to start out 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 current 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 revealed 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, known 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, known as G-proteins, to manage many 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 impression, each within the G protein coupled receptor biology discipline, and in artificial circuits or cell-based therapies. If you put a expertise on the market, it is at all times thrilling to see all of the artistic 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 attainable.”

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

Holding the keys

Whereas G-protein coupled receptors can activate varied 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 possibility.

“G-protein coupled receptors, usually, might 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’ve got 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 pal, the nanobody and peptide antagonist solely enable for insertion of the important thing beneath particular circumstances. This configuration not solely limits entry to the receptor but additionally makes it attainable to swap out the “proprietor” to alter the entry standards. This modularity, mixed with the considerable affect of G-proteins, means PAGER may allow an unbelievable variety of cell responses.

All of it works

To place PAGER by way of 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 kind of immune cell), and secrete therapeutic antibodies in response to the presence of tumor antigens.

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

The subsequent steps for PAGER contain exploring totally different purposes, simplifying its construction, and enhancing its capacity to function autonomously – corresponding to robotically delivering medicine upon receptor binding. Though nonetheless in early levels, 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’d love to use it to all kinds of locations, however we do not have the experience for that,” mentioned Kalogriopoulos. “We want individuals who really research the biology of a particular illness or mobile perform as a result of they know the right inputs and outputs. So I am actually excited for folks to take it and begin utilizing it.”