Nav: Home

A breakthrough in our understanding of how red blood cells develop

March 19, 2018

By taking a deep dive into the molecular underpinnings of Diamond-Blackfan anemia, scientists have made a new discovery about what drives the development of mature red blood cells from the earliest form of blood cells, called hematopoietic (blood-forming) stem cells.

For the first time, cellular machines called ribosomes -- which create proteins in every cell of the body -- have been linked to blood stem cell differentiation. The findings, published today in Cell, have revealed a potential new therapeutic pathway to treat Diamond-Blackfan anemia. They also cap off a research effort at Boston Children's Hospital spanning nearly 80 years and several generations of scientists.

Diamond-Blackfan anemia -- a severe, rare, congenital blood disorder -- was first described in 1938 by Louis Diamond, MD, and Kenneth Blackfan, MD, of Boston Children's. The disorder impairs red blood cell production, impacting delivery of oxygen throughout the body and causing anemia. Forty years ago, David Nathan, MD, of Boston Children's determined that the disorder specifically affects the way blood stem cells become mature red blood cells.

Then, nearly 30 years ago, Stuart Orkin, MD, also of Boston Children's, identified a protein called GATA1 as being a key factor in the production of hemoglobin, the essential protein in red blood cells that is responsible for transporting oxygen. Interestingly, in more recent years, genetic analysis has revealed that some patients with Diamond-Blackfan have mutations that block normal GATA1 production.

Now, the final pieces of the puzzle -- what causes Diamond-Blackfan anemia on a molecular level and how exactly ribosomes and GATA1 are involved -- have finally been solved by another member of the Boston Children's scientific community, Vijay Sankaran, MD, PhD, senior author of the new Cell paper.

"Much of the history of how this disorder works was written at Boston Children's," says Sankaran, who is a hematologist/oncologist and a principal investigator at the Dana-Farber/Boston Children's Cancer and Blood Disorders Center. "Now, we can move on to the next era of research -- what we can do to treat it."

Learning from an error of nature

Previous studies have found that many patients with Diamond-Blackfan anemia have mutated ribosomal protein genes. But the question has remained: Do these mutations have something to do with GATA1 and why do they only impair the maturation of red blood cells? In Diamond-Blackfan, other mature blood cells -- such as platelets, T cells and B cells -- still fare well despite mutations of ribosomal protein or GATA1 genes.

"There has been controversy over whether a ribosomal protein mutation changes the composition of the ribosomes or the quantity of the ribosomes," Sankaran says. "We know now that it is the latter."

By closely examining human cell samples from patients with Diamond-Blackfan anemia, Sankaran and his team of collaborators found that the quantity of ribosomes within blood cell precursors directly influences their ability to produce effective levels of GATA1, which, if you remember, is needed for hemoglobin production and also for red blood cell production.

Now, finally tying all the pieces together, Sankaran and his team have definitively found that a reduced number of ribosomes slashes the output of GATA1 proteins inside blood stem cells, therefore impairing their differentiation into mature red blood cells.

An opportunity for gene therapy

Their finding supports the hypothesis that the presence of GATA1 proteins in early blood stem cells helps prime them for differentiation into red blood cells. Without enough ribosomes to produce enough GATA1 proteins, these early cells simply never receive the signal to become red blood cells.

"This raises the question of whether we can design a gene therapy to overcome the GATA1 deficiency," Sankaran says. "We now have a tremendous interest in this approach and believe it can be done."

Although a bone marrow transplant from a matched donor can treat Diamond-Blackfan anemia, Sankaran says that a gene therapy would be advantageous since it would use a patient's own engineered cells, avoiding dangerous risks associated with graft versus host disease.

"I think what's great is that we can learn about developmental biology just by looking at our own patients very carefully," says Sankaran. "Genetic errors can give us the chance to pick apart the complex pieces of health and discover how they relate to one another."
-end-
In addition to Sankaran, additional authors of the new paper are Rajiv K. Khajuria, Mathias Munschauer, Jacob C. Ulirsch, Claudia Fiorini, Leif S. Ludwig, Sean K. McFarland, Nour J. Abdulhay, Harrison Specht, Hasmik Keshishian, D.R. Mani, Marko Jovanovic, Steven R. Ellis, Charles P. Fulco, Jesse M. Engreitz, Sabina Schütz, John Lian, Karen W. Gripp, Olga K. Weinberg, Geraldine S. Pinkus, Lee Gehrke, Aviv Regev, Eric S. Lander, Hanna T. Gazda, Winston Y. Lee, Vikram G. Panse and Steven A. Carr.

This research was supported by the National Institutes of Health (DK103794, R33 HL120791 and T32 HL007574), a Manton Center Endowed Scholar Award, a DBA Foundation and March of Dimes Basil O'Connor Scholar Award, a Boehringer Ingelheim MD Fellowship, the Swiss National Science Foundation, Novartis Foundation, Olga Maybenfisch Stiftung and the European Research Council (EURIBIO260676).

Boston Children's Hospital

Related Stem Cells Articles:

More selective elimination of leukemia stem cells and blood stem cells
Hematopoietic stem cells from a healthy donor can help patients suffering from acute leukemia.
Computer simulations visualize how DNA is recognized to convert cells into stem cells
Researchers of the Hubrecht Institute (KNAW - The Netherlands) and the Max Planck Institute in Münster (Germany) have revealed how an essential protein helps to activate genomic DNA during the conversion of regular adult human cells into stem cells.
First events in stem cells becoming specialized cells needed for organ development
Cell biologists at the University of Toronto shed light on the very first step stem cells go through to turn into the specialized cells that make up organs.
Surprising research result: All immature cells can develop into stem cells
New sensational study conducted at the University of Copenhagen disproves traditional knowledge of stem cell development.
The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.
Healthy blood stem cells have as many DNA mutations as leukemic cells
Researchers from the Princess Máxima Center for Pediatric Oncology have shown that the number of mutations in healthy and leukemic blood stem cells does not differ.
New method grows brain cells from stem cells quickly and efficiently
Researchers at Lund University in Sweden have developed a faster method to generate functional brain cells, called astrocytes, from embryonic stem cells.
NUS researchers confine mature cells to turn them into stem cells
Recent research led by Professor G.V. Shivashankar of the Mechanobiology Institute at the National University of Singapore and the FIRC Institute of Molecular Oncology in Italy, has revealed that mature cells can be reprogrammed into re-deployable stem cells without direct genetic modification -- by confining them to a defined geometric space for an extended period of time.
Researchers develop a new method for turning skin cells into pluripotent stem cells
Researchers at the University of Helsinki, Finland, and Karolinska Institutet, Sweden, have for the first time succeeded in converting human skin cells into pluripotent stem cells by activating the cell's own genes.
In mice, stem cells seem to work in fighting obesity! What about stem cells in humans?
This release aims to summarize the available literature in regard to the effect of Mesenchymal Stem Cells transplantation on obesity and related comorbidities from the animal model.
More Stem Cells News and Stem Cells Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.