Human Cell Atlas: The Plan to Map Every Cell in Your Body

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via ABC : Our bodies are made up of least 37 trillion cells, and scientists are teaming up around the world to map every single one of them.

A new project called the Human Cell Atlas hopes to discover what each of these cells do. And the plan is to put the information in an online database that any scientist can use.

It is a massive project that will transform our understanding of how the human body works and how to treat diseases, said Shalin Naik, who is co-leading the Australian research effort.

“We need to understand what cells look like, before we understand how they go wrong or how we might improve their function,” said Dr Naik of the Walter and Eliza Hall Institute.

It is the most ambitious undertaking in human biology research since scientists mapped the human genome, which took 20 years to complete.

“If the Human Genome Project was the part list of how to make a human, the Human Cell Atlas is how we put that together to make a functioning organism,” said Dr Naik.”

How to ‘profile’ a cell

When you think of cells, the beautiful images taken through microscopes probably come to mind.

But microscopic images just scratch the surface of what’s going on underneath, Dr Naik said.

“You’re looking at the amorphous blob of a cell and it’s got a particular shape and that’s very nice, but we want to know what’s going on inside, what are the mechanics of that cell what are the different proteins it has to perform its role in the body,” he said.

“It’s only when you start looking at the single cell level can you tease those differences apart.”

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Scientists want to know what genes are expressed — turned on or off — in each individual cell.

“We have 50,000 genes, but not all cells express all 50,000 of those genes. They only express a subset of those and that subset determines whether a cell becomes a muscle cell or a liver cell or a kidney cell.”

The key to this type of research is a recently developed technology called single cell RNA sequencing.

Until this technology arrived in 2009, scientists could only see a mish-mash of cells in tissue samples such as cancer tumours, but now they are able to peer into every single cell.

“We know the basics of most tissues, but there’s a level of specialisation we just didn’t know existed until we started looking at each tissue, cell by cell, and suddenly all these tissues got revealed,” Dr Naik said.

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University of Queensland researcher Joseph Powell said the technology has been a game-changer for medical research.

“We’ve very recently moved to a technological level where we can generate sequences for a single cell cheaply, robustly and quickly and we can do it for hundreds of thousands of cells in a single experiment,” said Dr Powell, who is co-leading the Australian research team with Dr Naik.

“It means we can start addressing some fundamental biological questions about why cells are doing different things in the human body.”

Even cells you think are exactly the same, such as skin cells, can have different functions.

Identifying what each type of cell does at the molecular level — there are at least 10-12 types of skin cell we know of — can help scientists understand why some people get diseases and others don’t.

Big data could lead to big breakthroughs

The Human Cell Atlas is the brainchild of Aviv Regev from the Broad Institute of MIT and Harvard in the US and Sarah Teichmann from the Wellcome Sanger Institute in the UK.

Dr Teichmann said comprehensive maps of all the cells in the body could have a huge impact on how we diagnose, monitor and treat disease.

“They could also help scientists understand how genetic variants impact disease risk, define drug toxicities, discover better therapies, and advance regenerative medicine,” she said.

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Dr Powell, who studies the lifecycle of cells looking for genetic triggers of disease, said the information would vastly improve screening for diseases, even before symptoms appeared.

“So if you think of cancer — even before tumours heavily metastasise they start shedding off little cells that float around in the blood. You would not have any symptoms but you could start detecting these things,” he said.

“And then we can start working towards treatments that can block those cells, kill them, make them do something else. All these things will be possible.”

He said the approach would make medicine truly personalised.

“It would allow clinicians and pathologists to not only tell you, ‘you have a disease’ but also say ‘right you’ve got cells doing the following things wrong so we’ll give you this particular drug’,” he said.

“I think it’ll lead to an absolute avalanche of medical breakthroughs.”

“And for me I think that’s why it’s important to get involved.

“We almost have a duty as scientists to drive these kinds of [projects].”

How will they build an atlas?

“The Human Cell Atlas is a resource of such ambition and scale that it will be built in stages, increasing in size, breadth, and resolution as technologies develop and understanding deepens over several years,” Dr Teichmann said.

The first phase of the project aims to profile 30 million to 100 million cells within five years.

Data from the first million cells — immune cells from blood and bone marrow from healthy donors — will be published on the database this month.

Ultimately, the scientists hope to build an atlas of at least 10 billion cells covering every tissue, organ and system in the body.

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Building the atlas will rely on some serious teamwork, number crunching, and cell donors.

The international team — that will include scientists from 14 research institutions in Australia — plan to research cells collected from anonymous donors from all over the world.

“We want to try to capture age, gender, ethnicity and also environmental context because that can also influence how our cells behave,” Dr Naik said.

“Part of the global effort is to really set some ground rules for whose tissue we’re going to take, what the makeup of those individuals looks like and how we do that in an ethically responsible way.”

He said while some cell types such as blood and skin were sourced from healthy people who agreed to participate in medical research, other cell types such as brain tissue needed to be obtained from people who have agreed to donate their tissues to science when they died.

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The power of open source

All the anonymous data will be put on a huge open source database built with support from the Chan Zuckerberg Initiative.

Dr Teichmann said the project was committed to open data sharing.

“Data will be released as soon as possible after it has been collected so it can be used immediately to further our understanding of human health and disease,” Dr Teichmann said.

Dr Naik said making the data publicly available would streamline research and future discoveries.

“By making it freely available we can focus on finding new nuggets of information that could be important for human health.”

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Source : ABC | Human Cell Atlas: The Plan to Map Every Cell in Your Body

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