Related Experiment Video
Updated: Jun 23, 2026
10:30
Immunocompetent Alveolus-on-Chip Model for Studying Alveolar Mucosal Immune Responses
Published on: May 31, 2024
Extracellular matrix influences alveolar epithelial claudin expression and barrier function
Michael Koval1, Christina Ward, Mary K Findley
1Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Emory University School of Medicine, Whitehead Biomedical Research Building, 615 Michael St., Suite 205, Atlanta, GA 30322, USA. mhkoval@emory.edu
Summary
Extracellular matrix components like fibronectin can promote rapid alveolar epithelial barrier formation in lung injury. However, laminin ultimately supports a more optimized barrier with higher resistance after five days of cell culture.
Area of Science:
- Cell Biology
- Biomaterials Science
- Pulmonary Medicine
Background:
- Lung injury triggers extracellular matrix remodeling, impacting lung regeneration.
- Alveolar epithelial barrier integrity is crucial for lung function and repair.
Purpose of the Study:
- To investigate how different extracellular matrix components influence alveolar epithelial barrier function.
- To examine the expression and function of tight junction proteins in response to matrix composition.
Main Methods:
- Rat alveolar epithelial type II cells were cultured on type I collagen, fibronectin, or laminin.
- Barrier resistance and tight junction protein localization (claudin-3, claudin-18, zonula occludens-1) were assessed.
Main Results:
- Cells on fibronectin rapidly formed high-resistance barriers with continuous claudin localization within 2 days.
- Fibronectin-cultured cells exhibited preferential chloride over sodium permeability.
- After 5 days, all matrix conditions supported high-resistance barriers, with laminin yielding the highest resistance.
- Increased claudin-18 and zonula occludens-1 expression correlated with barrier maturation.
Conclusions:
- Fibronectin promotes rapid but potentially suboptimal alveolar epithelial barrier formation.
- Laminin supports the development of a more optimized, high-resistance barrier over time.
- Matrix composition critically influences the kinetics and quality of alveolar epithelial barrier repair.
More Related Videos
Related Concept Videos
01:24Overview of Cell-Matrix Interactions
The extracellular matrix or ECM holds cells together to form a tissue and allows the cells within the tissue to communicate. ECM comprises proteins such as fibronectin, collagen, laminin, etc. The most abundant protein in this space is collagen. Collagen fibers are interwoven with carbohydrate-containing protein molecules called proteoglycans. ECM allows cell migration and provides a structural scaffold at cell adhesion that anchors the cell when the extracellular matrix proteins interact with...
01:26Extracellular Matrix
Unlike epithelial tissue, which is composed of cells closely packed with little or no extracellular space in between, connective tissue cells are dispersed in a matrix. This extracellular matrix (ECM) is composed of fibrous proteins like collagen, elastin, and fibronectin in a ground substance consisting of interstitial fluid, cell adhesion proteins, and proteoglycans. The proteoglycans form a gel-like material in the spaces between cells and provide hydration, buffering, binding, and force...
01:42The Extracellular Matrix
In order to maintain tissue organization, many animal cells are surrounded by structural molecules that make up the extracellular matrix (ECM). Together, the molecules in the ECM maintain the structural integrity of tissue as well as the remarkable specific properties of certain tissues.Composition of the Extracellular MatrixThe extracellular matrix (ECM) is commonly composed of ground substance, a gel-like fluid, fibrous components, and many structurally and functionally diverse molecules.
01:29The Extracellular Matrix
Overview
In order to maintain tissue organization, many animal cells are surrounded by structural molecules that make up the extracellular matrix (ECM). Together, the molecules in the ECM maintain the structural integrity of tissue as well as the remarkable specific properties of certain tissues.
Composition of the Extracellular Matrix
The extracellular matrix (ECM) is commonly composed of ground substance, a gel-like fluid, fibrous components, and many structurally and functionally diverse...
In order to maintain tissue organization, many animal cells are surrounded by structural molecules that make up the extracellular matrix (ECM). Together, the molecules in the ECM maintain the structural integrity of tissue as well as the remarkable specific properties of certain tissues.
Composition of the Extracellular Matrix
The extracellular matrix (ECM) is commonly composed of ground substance, a gel-like fluid, fibrous components, and many structurally and functionally diverse...
01:29Tight Junctions
Tight junctions are molecular seals between cells that prevent the leaking of fluids, ions, and other small solutes across cavities and compartments in multicellular organisms. They are mainly composed of claudin and occludin transmembrane proteins, and other proteins such as tricellulin and JAM (junctional adhesion molecule). All these proteins are 4-pass transmembrane proteins, except JAM, which is a single-pass transmembrane protein belonging to the immunoglobulin superfamily. The...
01:13Cell-matrix's Response to Mechanical Forces
In animal cells, the extracellular matrix allows cells within tissues to withstand external stresses and transmits signals from the outside of the cell to the inside. The extracellular matrix is extensive, and its composition varies between different types of tissues. For example, the reticular fibers and ground substance make up the ECM in loose connective tissue, while collagen and bone minerals make up the ECM of bone tissue.
Anchoring junctions mechanically attach a cell to the...
Anchoring junctions mechanically attach a cell to the...