With this CYTOO Story, you can discover how Amandine Pitaval et al restore cell function on micropatterns and empower cells to grow a Primary Cilium. The Primary Cilium is an antenna-like structure that emanates from the surface of virtually all cells in the mammalian body. It acts as both a biochemical and mechanical sensor and is directly connected to the cell’s cytoskeleton. Primary cilia are known as key coordinators of signaling pathways during development and in tissue homeostasis. This paper brings new elements to a better understanding of human diseases and developmental disorders, since defective cilia are involved in many pathological conditions.

1. “... the cell’s microenvironment is of utmost
importance in eliciting proper cell function
and adhesive micropatterns are a very
powerful tool to properly control
that cell microenvironment
in vitro” Restoring Cell Function
Manuel Théry, PhD, iRTSV, CEA on micropatterns:
Empowering cells to grow
a Primary Cilium
The Primary Cilium is an antenna-like structure that emanates from
the surface of virtually all cells in the mammalian body. It acts as both
a biochemical and mechanical sensor and is directly connected to the cell’s
cytoskeleton. Amandine Pitaval, under the guidance of Manuel Théry, has recently
published in the Journal of Cell Biology a paper investigating the effect of the cell’s
microenvironment on ciliogenesis. Primary cilia are known as key coordinators of signaling
pathways during development and in tissue homeostasis. This paper brings new elements to
a better understanding of human diseases and developmental disorders, since defective cilia are
involved in many pathological conditions.
When the authors initiated the subject of ciliogenesis at the IRTSV Institute in Grenoble, they started by
questioning the common understanding that cell-cell contacts upon cell confluence were necessary for
cultured cells to initiate the growth of the primary cilium, in addition to the required cell cycle arrest in
G0 promoted by low serum medium.
S=500µm2
S=3000µm By using disk shaped micropatterns of various sizes,
2
they demonstrated that this hypothesis was flawed.
Ciliogenesis occurs when cells are less spread out
Actin
(ie on smaller disks) and is inhibited when cells
spread out flat on the larger disks, indicating
that the overall 3D shape of the cell is key
Cilium
in ciliogenesis.
Zoom
Ciliogenesis No Ciliogenesis
Figure 1: on the left, cells growing on 500μm² disks exhibit a diffuse actin network
and a primary cilium, whereas on the right, cells growing on large disks show a strong
network of stress fibers and no ciliogenesis. ©2012, Rockefeller University Press.
Originally published in The Journal of Cell Biology. 191: 303-312.

2. Innovation in Cell-based Assays
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www.cytoo.com In just a simple
Cell Architects experiment, they
7 parvis Louis Néel, BHT, obtained consistent growth
BP 50 - 38040 Grenoble of long primary cilia on individual
FRANCE
cells patterned on 500μm2 disks
Inc (Figure 2).
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Cilia length was directly correlated with the size of the
MA 02138, USA disk patterns.
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“We also obtained a totally unexpected result from this work”,
commented Manuel Théry, «cells stretched out on large disks had an
inverted polarity compared to cells on the smaller disks. In the first case, the
centrosome was stuck under the nucleus against the support and in the second,
the centrosome was at the apex of the cell, perfectly positioned for cilia development
and function. Once again, the cell’s microenvironment is of utmost importance in eliciting
proper cell function and adhesive micropatterns are a very powerful tool to properly control that
cell microenvironment in vitro».
In terms of a Ciliogenesis Assay, these results transpose into a very straightforward assay to study drug effects
on initiation, growth and maintenance of the primary cilia. Thousands of small disks can be patterned at the
bottom of each well of a microplate offering standardized ciliated cells for screening applications.
(%)
90
“In view of the growing list of pathologies and syndromes
80 being linked to cilia defects, also collectively known as
70 ciliopathies, such as polycystic kidney disease, polydactily,
60 retinopathy, obesity, mental retardation and a host of
50 other pathologies involving most of the major body
40
organs, including kidney, limb, brain, retina, liver,
30
20
bones, this assay has huge promise in addressing
10 the fine detection and quantification of drugs
0 affecting or promoting proper cilia initiation
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and development” concluded Michel
Adhesive disk area (µm²) Bornens, CSO of CYTOO.
Figure 2: Proportion of ciliated cells 48h after serum
starvation
Further reading:
Pitaval A, Tseng Q, Bornens M, Théry M. Cell shape and contractility regulate ciliogenesis in cell cycle-arrested cells. J. Cell Biol. 2010;191(2):303–312.
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