The human body is home to approximately 37 trillion cells. In one person, all of those cells will have nearly identical DNA, but the way those genes are expressed—how their activity is dialed up or down—creates the hundreds of cell types that make a human. When that expression is thrown off-kilter, disease can arise.
Until recently, studying the gene expression differences between single cells was difficult. Now it’s the basis of a Cambridge, Mass.-based start-up called Celsius Therapeutics, which is launching today with $65 million in series A funding led by Third Rock Ventures.
The company was cofounded by Aviv Regev, a computational biologist at the Broad Institute of Harvard & MIT and a pioneer in the budding field of single-cell genomics. As the name implies, single-cell genomics compares genetic data between cells that may look the same but that actually have gene-expression differences, measured by the amount of RNA molecules produced from the DNA code.
In the past few years, Regev’s lab has garnered attention by using single-cell genomics to offer a glimpse at the untapped diversity of human cell types waiting to be probed. Her work spurred the creation of the international Human Cell Atlas project, which she coleads and hopes will improve understanding of the human body in both health and disease.
About two years ago, Christoph Lengauer, a partner at Third Rock, met Regev to discuss single-cell genomics and its potential uses in drug discovery. “When I saw the potential of this technology, I knew this had to be turned into a company,” he recalls. Celsius was soon founded, even though it was unclear what the impact of the technology might be.
After two years of working in stealth, Lengauer, who is now president of Celsius, is convinced that single-cell genomics will expose new drug targets missed by traditional genomics.
When diseases are caused by a minority of cells, Lengauer explains, those cells can get lost in the noise of the body. Traditional techniques for measuring gene expression use many cells that are blended and sequenced together.
“It is very much like a smoothie,” Lengauer explains. What comes out of the blender, or sequencer, is an average of what’s thrown in. If a smoothie tastes bad, it can be hard to pinpoint the source of the offensive flavor. Similarly, in a large population of cells, it can be difficult to tease the minority of cells driving the disease out from all the sick cells affected by the disease.
“Single-cell genomics, on the other hand, is like a fruit platter,” Lengauer says. Celsius is betting that by comparing gene expression between many individual cells, single-cell genomics can pinpoint new drug targets. “We can now discover targets that are important for these diseases that were lost in the blender before,” Langauer says.
Celsius isn’t disclosing any specific drug programs, but Lengauer says the start-up is focused on cancer and autoimmune diseases. At the moment, it employs 16 gene hunters, drug discoverers, and data scientists. In fact, developing systems capable of handling the massive amounts of data needed to compare gene expression between cells is another focus of the company—and potentially a reason that GV, formerly known as Google Ventures, is one of the start-up’s investors.