Quantitative characterization of a cardiac progenitor cell epithelium

Host laboratory and collaborators

Robert G. Kelly / IBDM /

Paul Villoutreix / LIS /


Understanding how cellular and tissue-­‐wide forces contribute to growth and form during organogenesis is a major  challenge  in  developmental  biology.  The  vertebrate  heart  tube  extends  as  a  consequence  of  the  progressive addition of second heart field (SHF) progenitor cells within an epithelial sheet to the arterial and venous poles of the heart. Perturbation of this process results in congenital heart defects (CHD), affecting 1% of live births. T-­‐box transcription factor genes implicated in CHD regulate the emergence of a boundary segregating  SHF  cells  to  alternate  cardiac  poles.  In  addition,  epithelial  features  of  the  SHF,  including  cell longation,  polarity,  clonal  anisotropy  and  epithelial  tension,  have  been  identified  as  regulatory  targets during  heart  tube  elongation  (Cortes  et  al.,  Circ  Res  2018).  However,  the  relationship  between  epithelial  properties  and  the  patterning  of  progenitor  cell  subpopulations  in  the  SHF  remains  unknown.  Multidisciplinary quantitative approaches will be undertaken to address this question in the mouse embryo.


Epithelial polarity, Congenital Heart Diseases, Heart Morphogenesis


This  project  will  provide  new  mechanistic  insights  into  cardiac  morphogenesis  and  the  origins  of  CHD  by integrating findings from patterning and cell biology in a progenitor cell epithelium.  The candidate will 1)  perform a quantitative phenomenological analysis of epithelial cellular properties (cell elongation, polarity, anisotropy  and  epithelial  tension)  and  clonal  growth  patterns  in  the  SHF;  2)  investigate  the  relationship  between progenitor cell patterning and epithelial features using embryo culture and mouse genetics.

Proposed approach (experimental / theoretical / computational)

The  following  multidisciplinary  in  vivo  approaches  will  be  undertaken:

1)  Quantitative  phenomenological  analysis  of  epithelial  cellular  properties  during  mouse  heart  tube  elongation  including  spatiotemporal  mapping  of  cell  shape  and  mechanical  stress  using  state  of  the  art  fluorescent  microscopy  in  cleared  embryos. In addition, clonal growth patterns will be analysed in the progenitor cell epithelium using a novel inducible  SHF  Cre  driver  combined  with  a  conditional  confetti  reporter.

2)  Investigation  of  epithelial  properties of SHF cells consequent to perturbed progenitor cell patterning. Mice carrying mutations in the arterial and venous pole regulatory genes Tbx1 and Tbx5, implicated in 22q11.2 and Holt-­‐Oram syndrome, will  be  analysed.  including  investigation  of  the  role  of  increased  aPCKz  levels  in  Tbx1  mutant  embryos  in  regulating  epithelial  polarity.  The  combination  of  mouse  genetics,  imaging  and  quantitative  analysis  will  contribute to modelling how the epithelial progentior cell state is regulated during early heart development.


Investigating heart morphogenesis is a complex goal that requires integration of different disciplines. This project  combines  quantitative  visualization  with  molecular  genetic  approaches  and  phenomological  modeling applied to an in vivo mouse model. This interdisciplinary approach will allow the identification of novel regulatory mechanisms that control heart tube elongation, a critical step in cardiac development, with significant  biomedical  implications.  The  PhD  project  will  be  carried  out  in  a  collaboration  between  an  experimental  research  group  studying  heart  development  (Kelly)  and  a  group  applying  mathematical  modeling and quantitative approaches to investigate morphogenetic mechanisms (Villoutreix). The student will benefit from experimental and theoretical synergies as well as IBDM and CENTURI resources to enhance the successful implementation of this project and uncover new mechanisms implicated in organogenesis.

Expected profile

The  candidate  will  be  interested  in  understanding  the  basic  mechanisms  driving  morphogenesis  and  epithelial  biology.  The  project  will  be  largely  experimental  with  an  important  component  of  quantitative  image analysis. Experience in molecular genetics, mouse handling and fluorescence microscopy will be an advantage but not essential.