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Integrins inhibit LPS-induced DNA strand breakage in cultured lung endothelial cells
D G Hoyt1, R J Mannix, M E Gerritsen
1Department of Pharmacology, University of Pittsburgh School of Medicine, Pennsylvania 15261, USA.
Abstract:
Collagen inhibits acute DNA strand breakage and apoptosis in sheep pulmonary artery endothelial cells (SPAEC) treated with lipopolysaccharide (LPS). Here we tested the ability of major basement membrane components, type IV collagen, laminin and fibronectin, and integrin ligands and anti-integrin antibodies to inhibit DNA breakage caused by LPS in SPAEC and BALB/c murine lung endothelial cells (MLEC). In situ labeling of DNA strand breaks with terminal deoxynucleotidyl transferase revealed similar DNA breakage in attached SPAEC and MLEC within 2 h after incubation with 1 microgram LPS/ml. Acute DNA strand breakage was reduced in cells plated on gelatin, type IV collagen, laminin, cellular fibronectin, or plasma fibronectin. DNA breakage was also suppressed by plating cells on surfaces coated with the integrin ligand hexapeptide, GRGDSP (40 micrograms/cm2), but not with GRADSP. LPS-induced DNA strand breakage was inhibited in MLEC plated on surfaces coated with antibodies to murine alpha 5-, beta 1, or beta 3-integrin subunits. Addition of anti-integrin antibodies, but not GRGDSP, to the medium above cell monolayers inhibited strand breakage. Despite similar acute DNA breakage, MLEC exhibited less detachment and apoptosis than SPAEC, consistent with a difference in the sensing or processing systems for apoptosis in these two cell types. These results demonstrate that extracellular matrices and integrin activation can inhibit the genotoxicity of LPS.
Insights
Extracellular matrices like collagen and fibronectin, along with integrin activation, significantly reduce DNA damage and cell death caused by lipopolysaccharide (LPS) in lung endothelial cells.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Lipopolysaccharide (LPS) induces acute DNA strand breakage and apoptosis in endothelial cells.
- Basement membrane components and integrin signaling are crucial for endothelial cell function and survival.
Purpose of the Study:
- To investigate the protective effects of basement membrane components and integrin activation against LPS-induced genotoxicity.
- To compare the cellular responses of sheep pulmonary artery endothelial cells (SPAEC) and murine lung endothelial cells (MLEC) to LPS.
Main Methods:
- In situ labeling of DNA strand breaks using terminal deoxynucleotidyl transferase.
- Culturing endothelial cells on surfaces coated with extracellular matrix proteins (collagen, laminin, fibronectin) or integrin ligands (GRGDSP).
- Utilizing anti-integrin antibodies to block integrin signaling pathways.
Main Results:
- LPS induced similar acute DNA strand breakage in both SPAEC and MLEC.
- Plating cells on type IV collagen, laminin, fibronectin, or gelatin reduced DNA breakage.
- The integrin ligand GRGDSP and anti-integrin antibodies inhibited LPS-induced DNA strand breakage.
- MLEC showed less detachment and apoptosis than SPAEC despite similar DNA breakage.
Conclusions:
- Extracellular matrices and integrin activation effectively inhibit LPS-induced genotoxicity in lung endothelial cells.
- Differences in apoptosis signaling may exist between SPAEC and MLEC.
- Integrin-mediated signaling plays a protective role against LPS-induced cellular damage.