Biophysical Society Thematic Meeting

Mechanobiology of Disease

Poster Abstracts

14-POS

Board 14

E-cadherin Force Contributes to Lumen Homeostasis in Epithelial Acini

Vani Narayanan,

Daniel E. Conway

Virginia Commonwealth University, Richmond, VA, USA.

Little is known about the effects of protein-level mechanical forces on cell behavior in the

context of an organized tissue structure. Epithelial cells cultured in a 3D environment comprising

of extracellular matrix proteins form hollow spheroids of polarized cells known as acini or cysts.

We hypothesized that forces across cell-cell junctions, specifically E-cadherin, are important

regulators of these structures. Using a FRET-based tension biosensor in MDCK cells grown in

Matrigel, we observed that E-cadherin forces were higher in 3D acini as compared to 2D

monolayers. Using forskolin and a CFTR inhibitor to increase and decrease acini lumen pressure,

respectively, we observed that E-cadherin force was affected by lumen pressure. Additionally,

we were able to show that increased lumen pressure induces cell proliferation, requiring

cytoskeletal-connected E-cadherin. Thus, changes in lumen pressure can regulate epithelial

proliferation through E-cadherin forces, similar to prior work showing E-cadherin forces mediate

stretch-induced proliferation in 2D. Next, we observed that cells expressing low- and zero-force

mutants of E-cadherin had impaired lumen formation (multiluminated or complete absence of a

lumen). In the case of the low-force mutant we were able to increase E-cadherin force and rescue

acini to a single lumen using forskolin, further substantiating the role of E-cadherin force in acini

homeostasis. Finally, we observed that E-cadherin force was reduced during the process of

TGFß-induced EMT. Pre-treatment with forskolin was sufficient to block E-cadherin force

changes, EMT, and lumen filling in TGFß treated cells. We are currently investigating if TGFß

reduces E-cadherin force by altering lumen pressure, and also to determine if forskolin prevents

EMT is through lumen pressure and/or E-cadherin forces. The major conclusion of these studies

is that E-Cadherin tensile forces, which are modulated by lumen pressure, regulate the formation

and homeostasis of epithelial acini.