What question did this study set out to answer?

To clarify the functional role of the tight junction protein occludin in epithelial cell physiology, cytoskeletal organization, and barrier properties.

February 2, 2005AJP Cell Physiology

Knockdown of occludin expression leads to diverse phenotypic alterations in epithelial cells

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Authors

AYAlan S.L. YuUniversity of Kansas Medical Center KMKarin M. McCarthyHarvard University SFStacy A. FrancisHarvard University

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Implication

In vitro study demonstrates altered ion permeability and impaired cytoskeletal signaling in occludin-deficient epithelial cells, suggesting occludin regulates actin dynamics via Rho pathways.

Key Points

To clarify the functional role of the tight junction protein occludin in epithelial cell physiology, cytoskeletal organization, and barrier properties.
Stably knocked down occludin expression in Madin-Darby canine kidney II (MDCK II) cells using short interfering RNA (siRNA).
Assessed membrane lipid diffusion (fence function) with BODIPY-sphingomyelin and measured transepithelial electrical resistance (TER) and ion flux to evaluate gate function.
Challenged cells via apoptotic cell extrusion assays and acute cholesterol depletion to evaluate actin cytoskeleton dynamics and Rho-GTP signaling.
Occludin knockdown preserved membrane fence function but decreased claudin-1 and claudin-7, increased claudin-3 and claudin-4, and left claudin-2 unchanged.
Occludin-deficient cells exhibited impaired apoptotic cell extrusion, failed to activate Rho-GTP upon cholesterol depletion, and did not experience the expected drop in transepithelial electrical resistance.
Steady-state transepithelial electrical resistance remained unchanged, yet occludin depletion increased permeability to inorganic cations and substantially increased permeability to large monovalent organic cations up to 6.96 Å, with negligible effects on chloride or mannitol flux.

Cite This Study

Yu et al. (2005) studied this question.

synapsesocial.com/papers/6a709bfce71d69abee08b893 https://doi.org/10.1152/ajpcell.00581.2004

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Implication

In vitro study demonstrates altered ion permeability and impaired cytoskeletal signaling in occludin-deficient epithelial cells, suggesting occludin regulates actin dynamics via Rho pathways.

Knockdown of occludin expression leads to diverse phenotypic alterations in epithelial cells

Discussion

Member takes

Implication

Key Points

Cite This Study

Knockdown of occludin expression leads to diverse phenotypic alterations in epithelial cells

Discussion

Member takes

Implication

Key Points

Cite This Study

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