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Expression and function of beta(1) and beta(3) integrins of human mesothelial cells in vitro
L Tietze1, J Bornträeger, B Klosterhalfen
1Institute of Pathology, Aachen University of Technology, Aachen, Germany.
Abstract:
Mesothelial cells (MC) and extracellular matrix (ECM) components are thought to play a pivotal regulatory role during the inflammatory-reparative response of serosal membranes. Integrins are known to serve as cellular ECM receptors, but mesothelial integrin expression and its function, particularly its role for attachment to different ECM components, remain to be elucidated. The aim of the present study was to characterize the integrin expression of human omentum majus derived MC (HOMC) in vitro by immunohistochemistry and to investigate their functional significance with regard to HOMC adhesion to fibronectin (fn), vitronectin (vn), collagen IV (coll IV), and laminin (ln). Mesothelial cells in vitro strongly expressed beta(1), beta(3), alpha(2), alpha(3), alpha(5), and alpha(v) chains. A weak reactivity was found for alpha(1) and alpha(6), but no alpha(4) reactivity was detectable. Compared to the control, fn, vn, coll IV, and ln caused a significant 2.6-, 2.2-, 2-, and 1.6-fold increase of HOMC adhesion, respectively. Inhibition studies revealed that HOMC attachment to fn is mediated by alpha(5)beta(1), alpha(v)beta(1), and alpha(v)beta(3), with a synergistic effect of alpha(5)beta(1) and alpha(v)beta(3). Adhesion to vn is mediated by alpha(v)beta(1) and alpha(v)beta(3). Integrins alpha(1)beta(1), alpha(2)beta(1), and alpha(3)beta(1) mediate adhesion to coll IV and ln. We suggest that the integrin expression and function of mesothelial cells described here play an important role in the interaction of MC with the ECM, particularly during the acute and chronic inflammatory-reparative response of serosal membranes.
Insights
Mesothelial cells (MC) express specific integrins that mediate their attachment to extracellular matrix (ECM) components like fibronectin and vitronectin. This integrin function is crucial for the inflammatory and reparative responses in serosal membranes.
Area of Science:
- Cell Biology
- Biochemistry
- Immunology
Background:
- Mesothelial cells (MC) and extracellular matrix (ECM) are key regulators of serosal membrane inflammation and repair.
- Integrins function as cellular receptors for ECM components, but their specific roles in mesothelial cells remain unclear.
Purpose of the Study:
- To characterize integrin expression in human omentum majus derived MC (HOMC) in vitro.
- To investigate the functional significance of these integrins in HOMC adhesion to fibronectin, vitronectin, collagen IV, and laminin.
Main Methods:
- Immunohistochemistry was used to determine integrin expression on HOMC.
- Adhesion assays were performed to assess HOMC attachment to various ECM components.
- Inhibition studies using specific integrin blocking antibodies were conducted.
Main Results:
- HOMC expressed beta(1), beta(3), alpha(2), alpha(3), alpha(5), and alpha(v) integrin chains strongly, with weak expression of alpha(1) and alpha(6).
- Fibronectin, vitronectin, collagen IV, and laminin significantly increased HOMC adhesion.
- Specific integrin-ECM interactions were identified, including alpha(5)beta(1), alpha(v)beta(1), and alpha(v)beta(3) for fibronectin adhesion.
Conclusions:
- Mesothelial cells exhibit distinct integrin expression profiles.
- These integrins play a significant role in mediating mesothelial cell adhesion to ECM components.
- This interaction is vital for the inflammatory-reparative processes in serosal membranes.