Developing, characterising and testing a humanised 3D in vitro bone model, capable of long-term osteocyte culture

This new ability to maintain osteocytes in culture represents a substantial breakthrough for
the bone research field and the technology now provides us with a unique opportunity to develop an in vitro
model, containing all three of the key cell types required for bone remodelling, that could replace some of the
currently used in vivo models.
Objectives
Develop an organotypic model of bone remodelling comprising human osteoclasts, osteoblasts and osteocytes.
Validate the ability of the model to recapitulate bone remodelling and response to existing drug treatments.
Miniaturise the assay into a format suitable for application as a drug screening tool.
Our self-structuring bone formation model (SSBM) has, for the first time, enabled differentiation and long-term
culture of osteocytes. Now we will use this unique organ culture technology to develop an in vitro model
that recapitulates the more physiologically and medically relevant scenario of bone remodelling. This
will require the incorporation and sustainment of osteoblasts and osteoclasts in addition to the osteocytes and
will necessitate substantially more complicated readouts to assess the activity of each of the three cell types
present and the integrity and composition of the bone produced.
We will use our SSBM as an active, living substrate to support the additional cell types required for bone
remodelling: Osteoblasts and osteoclasts. We will then validate the resulting organotypic model of bone
remodelling and move towards miniaturisation to produce a screening platform that can be used to test novel
drugs for efficacy.
Hypotheses: 1.
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The SSBM constructs will support osteoblast survival, maturation and bone matrix production
and mineralisation by providing a physiological environment and stimulation through cellular
interactions with osteocyte canaliculi.
The SSBM will support osteoclast survival, maturation and bone resorption activity (as
above).
Communication between osteoblasts, osteoclasts and osteocytes via direct cell contact and
secretion of cytokines/growth factors (e.g. RANKL and OPG) will regulate bone resorption
rates resulting in an organotypic model of bone remodelling.
The organotypic model will be useful as a screening platform to test novel therapeutics
Future 3Rs Impact: This project involves the development of our ground-breaking osteocyte-culture
method into a more medically relevant model, its validation as an accurate and useful model of a
physiological process and its application as a drug screening tool.