For the first time, cellular machines called ribosomes have been linked to blood stem cell differentiation. The findings have revealed a potential new therapeutic pathway to treat Diamond-Blackfan anaemia. They also cap off a research effort at Boston Children’s Hospital spanning nearly 80 years and several generations of scientists.
Diamond-Blackfan anaemia is a severe, rare, congenital blood disorder. The disorder impairs red blood cell production, impacting delivery of oxygen throughout the body and causing anaemia. Forty years ago, Boston Children’s Hospital research determined that the disorder specifically affects the way blood stem cells become mature red blood cells. 10 years later, Stuart Orkin, also from Boston Children’s Hospital, identified a protein called GATA1. His studies showed that it was a key factor in the production of haemoglobin. This is the essential protein in red blood cells that is responsible for transporting oxygen.
In more recent years, genetic analysis has revealed that some patients with Diamond-Blackfan have mutations that block normal GATA1 production.
So, what causes Diamond-Blackfan anaemia on a molecular level and how exactly ribosomes and GATA1 are involved? Previous studies have found that many patients with D.B anaemia have mutated ribosomal protein genes. In Diamond-Blackfan, other mature blood cells, such as platelets, T cells and B cells are still considered as a cause/attribution, despite mutations of ribosomal protein or GATA1 genes.
By closely examining human cell samples from patients with Diamond-Blackfan anaemia, a team of research collaborators found that the quantity of ribosomes within blood cell precursors directly influences their ability to produce effective levels of GATA1, which is needed for haemoglobin production and also for red blood cell production.
The 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.