Francis Crick Institute researchers have used live imaging to
track human blood stem cells in the bone marrow as they seek out
their preferred environment, or niche.
The team hopes that learning more about blood stem cells -
called haematopoetic stem cells or HSCs - and the HSC niche will
evenutally help them understand leukaemia stem cells and their
niche, and potentially lead to new ways to treat the cancer.
The research was led by Dr Dominique Bonnet at the Crick. She
explained: "The niche is an important regulator of HSC fate. This
means that understanding where in the bone marrow HSCs go and their
niche will give us information about which cells and which
molecules secreted by different tissues play a role in regulating
HSCs.
"Scientists have made advances in understanding interactions
between mouse HSCs and their niche but, until now, little was known
about communication between human HSCs and their immediate
environment."
Dr Bonnet's team used a technique called intravital imaging to
track human HSCs translanted into mice that have deficient immune
systems - meaning they wouldn't react against the human HSCs.
The results showed that after transplanation the human HSC cells
entered the bone marrow of the mice and kept moving in search of
the right environnment. When they found it they suddenly stopped -
in contrast to more developed types of cells, which do not
stop.
Dr Bonnet said: "Our paper proposes that, to better define the
HSC niche, we should look at the movement of HSCs and define their
niche environment when they stop moving. Intravital imaging is the
only technique that can determine where in the bone marrow HSCs
stop moving and therefore where that niche is.
"In the future, we hope to use a similar imaging technique
to define the leukaemia stem cell niche. We don't know
whether this is the same as the normal HSC niche, and whether the
two types of stem cell compete for the same niche. Understanding
this could help us understand the external factors that maintain
leukaemia stem cells and thus help us develop new strategies to
eradicate them."
The paper, Different Motile Behaviors of Human Hematopoietic Stem versus
Progenitor Cells at the Osteoblastic Niche, is published inStem Cell Reports.