How a map of our cells could help treat disease
- Researchers have unveiled the progress they have made in creating a map of the cells of the human body.
- They say such a map could help diagnose and treat a variety of diseases.
- They compare the research to the Human Genome Project, which has sequenced every gene in the human genome.
Almost 20 years ago, the decade
This is a groundbreaking achievement that has contributed to major advances in biomedical technology and research.
This week, a potentially even more momentous achievement was showcased as the Atlas of human cells (HCA) has unveiled detailed maps of more than one million individual cells in 33 organs and systems.
The data, published in four major studies in the journal Science, represents the most comprehensive intertissue cell atlases in the world. This is a major stepping stone towards the HCA’s goal of mapping all cell types in the human body.
“The Human Cell Atlas is transforming our understanding of biology and disease,” said Sten Linnarsson, Ph.D., professor at the Karolinska Institutet in Sweden and member of the HCA organizing committee. “These intertissue studies represent an important step for HCA and single-cell biology by allowing systematic and in-depth comparison of the same cell types across development and into adulthood. They are a big step forward in generating a human cell atlas of all cell types in the human body, laying the foundation for a new era of diagnostics, healthcare and precision medicine.
During an online press conference, Sarah A. TeichmannPh.D., co-founder and principal leader of the international HCA consortium and head of cell genetics at the Wellcome Sanger Institute in Cambridge, England, likened the project’s goal to creating a “Google map of the human body – a ‘Street View’ map of all cells and tissues.
“What [the HCA] really opens up is the ability to understand fabrics in all their glory,” added Aviv Regev, Ph.D., co-founder of the project and fellow of the Broad Institute of MIT and Harvard University in Massachusetts.
The results – and those that promise to follow – will help researchers understand diseases, vaccine development and areas such as tumor immunology and regenerative medicine, experts said.
For example, Teichmann said, research has already revealed “how immune cells grow in new and unexpected ways” — in the gut, thymus and other tissues, not just bone marrow.
Regev said cell mapping “helps us understand precisely where disease is occurring” at the cellular level.
“People often think the genome is a blueprint, but it’s really a list of parts,” Stephen Quake, Ph.D., founder of Quake Lab, a biological research center at Stanford University in California, told Healthline.
Using machine learning, HCA researchers’ ability to separate tissue into individual cells for analysis provides insight into how these genetic “parts” work together throughout the body.
“The genome is the list of parts, but it’s not the operator – it’s the cells,” Regev added. “Once you have the genes, you have to understand where they operate.”
Regev compared the HCA project to the “Human Genome Project, but designed for the 21st century”.
“The HCA is a completely open process, with over 2,000 scientists in 83 countries,” she said. “That was not possible in the 1990s.”
Cell mapping will be particularly valuable for drug development, gene therapy and cell therapy, the experts said.
“If you’re targeting a particular cell, you want to know where else in the body that cell is expressed,” Quake said.
“Knowing where your target is expressed is crucial to preventing toxicity,” Regev added.
In one of four original studiesWellcome Sanger Institute researchers sequenced the RNA of 330,000 individual immune cells to better understand how immune cells function in different tissues.
“By comparing particular immune cells in multiple tissues from the same donors, we identified different ‘flavors’ of memory T [immune] cells in different areas of the body, which could have big implications in the management of infections,” Teichmann said. “Our freely available data will contribute to the Human Cell Atlas and could serve as a framework for the design of vaccines, or to improve the design of immune therapies to attack cancers.”
In a second study, a research team led by the Sanger Institute has created a comprehensive atlas of the development of the human immune system. The study included tissues involved in the formation of blood and immune cells and revealed that certain types of cells are lost as humans age. The researchers said the results can strengthen in vitro cell engineering and regenerative medicine research.
Regev led a third study who used machine learning algorithms to analyze frozen cellular material, overcoming a significant hurdle in a field of research that must typically rely on fresh tissue for analysis. The 200,000 cells added to the atlas by the Broad Institute team have been successfully linked to 6,000 single-gene diseases and 2,000 complex genetic diseases.
Regev said the study “paves the way for studies of tissue from entire cohorts of patients at the single-cell level.”
“We were able to create a new roadmap for multiple diseases, by directly linking cells to human disease biology and disease risk genes in tissues,” she said.
Finally, a study by Quake and his colleagues at the Chan Zuckerberg Biohub used single-cell RNA sequencing of live cells to analyze multiple organs from a single donor.
This allowed comparisons of different tissues while controlling for factors such as genetic background, age, and environmental effects.
The resulting cell atlas, which encompasses more than 400 cell types, has been dubbed “The Tabula Sapiens”.
“The Tabula Sapiens is a reference atlas that provides molecular definition of hundreds of cell types in 24 organs of the human body,” Quake said.
The results revealed new insights into cell biology, including how the same gene can be spliced differently in various cell types and how clones of immune cells can be shared between tissues.