Article
Patterning and folding of intestinal villi by active
mesenchymal dewetting
Graphical abstract
Highlights
d
Mesenchymal aggregates generate forces that fold the
mammalian intestinal epithelium
d
Active and fluid-like properties of aggregates program tissue
geometry and pattern
d
Matrix metalloproteinases fluidize the subepithelial
mesenchyme to initiate aggregation
d
Mesenchymal patterning conceptually resembles water
dewetting from a hydrophobic surface
Authors
Tyler R. Huycke, Teemu J. Ha
̈
kkinen,
Hikaru Miyazaki, ..., Dario Boffelli,
Ophir D. Klein, Zev J. Gartner
Correspondence
ophir.klein@cshs.org (O.D.K.),
zev.gartner@ucsf.edu (Z.J.G.)
In brief
Subepithelial mesenchyme behaves like a
dewetting fluid to pattern and fold the
intestinal epithelium, initiating the
formation of villi.
developmental time
epithelium
mesenchyme
PDGFRA
High
PDGFRA
Low
Fluid-like PDGFRA
High
aggregates
fold the
epithelium
to initiate villi
PDGFRA
High
dewets from
PDGFRA
Low
tissue
Tissue Scale
Dewetting of a thin liquid film into
droplets
Dewetting of intestinal mesenchyme into active cell
droplets
Fetal Intestine
Proximal-distal axis
Fibrillar ECM
Non-Fibrillar ECM
PDGFRA
High
PDGFRA
Low
Solid-like
Fluid-like
(dewetting)
Fluid-like
(droplet)
Cell Scale
Highly aligned & elastic
cell-matrix composite
Tissue fluidization by
MMP-mediated
matrix
remodeling
Formation of cohesive
mesenchymal
aggregates
Subepithelial mesenchyme
Less PDGFRA
High
More PDGFRA
High
Control of fold size and spacing
Engineering
Approaches
Self-organized patterning
and coarsening
Reconstitution of
interfacial folding
Huycke et al., 2024, Cell
187
, 3072–3089
June 6, 2024
ª
2024 The Authors. Published by Elsevier Inc.
https://doi.org/10.1016/j.cell.2024.04.039
ll
Article
Patterning and folding of intestinal villi
by active mesenchymal dewetting
Tyler R. Huycke,
1,2,11
Teemu J. Ha
̈
kkinen,
1,2,11
Hikaru Miyazaki,
1,2,11
Vasudha Srivastava,
1
Emilie Barruet,
3
Christopher S. McGinnis,
1
Ali Kalantari,
1,2
Jake Cornwall-Scoones,
4
Dedeepya Vaka,
3
Qin Zhu,
1
Hyunil Jo,
1
Roger Oria,
5,6,7,8
Valerie M. Weaver,
5,6,7,8
William F. DeGrado,
1
Matt Thomson,
4
Krishna Garikipati,
9
Dario Boffelli,
3
Ophir D. Klein,
2,3,
*
and Zev J. Gartner
1,10,12,
*
1
Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
2
Program in Craniofacial Biology and Department of Orofacial Sciences, University of California, San Francisco, San Francisco, CA, USA
3
Department of Pediatrics, Cedars-Sinai Guerin Children’s, Los Angeles, CA, USA
4
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
5
Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA
94143, USA
6
Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA
94143, USA
7
Comprehensive Cancer Center, Helen Diller Family Cancer Research Center, University of California, San Francisco, San Francisco, CA
94143, USA
8
Department of Bioengineering and Therapeutic Sciences, Department of Radiation Oncology, University of California, San Francisco, San
Francisco, CA 94143, USA
9
Departments of Mechanical Engineering, and Mathematics, University of Michigan, Ann Arbor, MI, USA
10
Chan Zuckerberg Biohub, San Francisco, CA, USA
11
These authors contributed equally
12
Lead contact
*Correspondence:
ophir.klein@cshs.org
(O.D.K.),
zev.gartner@ucsf.edu
(Z.J.G.)
https://doi.org/10.1016/j.cell.2024.04.039
SUMMARY
Tissue folds are structural motifs critical to organ function. In the intestine, bending of a flat epithelium into a
periodic pattern of folds gives rise to villi, finger-like protrusions that enable nutrient absorption. However, the
molecular and mechanical processes driving villus morphogenesis remain unclear. Here, we identify an
active mechanical mechanism that simultaneously patterns and folds the intestinal epithelium to initiate villus
formation. At the cellular level, we find that PDGFRA+ subepithelial mesenchymal cells generate myosin II-
dependent forces sufficient to produce patterned curvature in neighboring tissue interfaces. This symme-
try-breaking process requires altered cell and extracellular matrix interactions that are enabled by matrix
metalloproteinase-mediated tissue fluidization. Computational models, together with
in vitro
and
in vivo
ex-
periments, revealed that these cellular features manifest at the tissue level as differences in interfacial ten-
sions that promote mesenchymal aggregation and interface bending through a process analogous to the
active dewetting of a thin liquid film.
INTRODUCTION
Many organs comprise functional epithelial sheets overlying
mesenchymal stroma, connected through a common basement
membrane interface. A critical step in organ morphogenesis and
symmetry breaking is the folding of these tissue interfaces, often
occurring in Turing patterns hypothesized to emerge through
reaction-diffusion mechanisms or mechanical instabilities.
1–8
Distinct tissues generate stereotyped folds,
1
,
9–13
including
crypts and villi of the intestine,
2
,
14–16
that contribute to organ
function. Although many epithelia can fold themselves,
17
classic
epithelial-mesenchymal recombinations have suggested an
inductive capacity of the mesenchyme in driving epithelial shape
changes.
18–20
Interfacial folding can arise through local force
generation, such as apical/basal epithelial constriction, or more
global forces, such as mechanical instabilities emerging from dif-
ferential growth across tissues.
21
How interfacial folding occurs
robustly across biophysical environments and is mechanistically
coupled with tissue patterning is a fundamental question with im-
plications for tissue engineering, developmental biology, and
regenerative medicine.
In the fetal small intestine, the emergence of positive curvature
at the epithelial-mesenchymal interface demarcates the sites
of forming villi, elongated tissue protrusions that expand its
absorptive surface area at least 10-fold.
22
Postnatally, the emer-
gence of negative curvature at this interface gives rise to crypts
ll
OPEN ACCESS
3072
Cell
187
, 3072–3089, June 6, 2024
ª
2024 The Authors. Published by Elsevier Inc.
This is an open access article under the CC BY license (
http://creativecommons.org/licenses/by/4.0/
).