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Extracellular matrix oxidation modulates survival, NF-kappaB translocation, and MAPK activity in mesangial cells
Sergei Kochlatyi1, Nora Gibbons, Joseph Mattana
1Department of Medicine, Long Island Jewish Medical Center, New Hyde Park, New York 11040, USA.
Abstract:
Inflammatory injury to the kidney may oxidize extracellular matrix proteins. These changes appear to impair adhesion of glomerular mesangial cells and might impact signaling mechanisms in these cells. In this study we evaluated how extracellular matrix oxidation could modulate the development of apoptosis as well as the activity of the transcription factor NF-kappaB and that of the MAPK family members ERK-1,2 and JNK. Exposure of mesangial cells to oxidized matrix enhanced the percentage of apoptotic cells. Western blot analysis revealed diminished levels of the phosphorylated form of ERK-1,2 in cells on oxidized matrix, while levels of phosphorylated JNK were increased. Cells on unmodified matrix were found to have rapid translocation of the p65 subunit of NF-kappaB, which was attenuated in cells on oxidized matrix. These findings suggest that extracellular matrix oxidation may impair survival of mesangial cells in association with decreased levels of pERK-1,2, increased levels of pJNK, and diminished nuclear translocation of the transcription factor NF-kappaB.
Insights
Kidney injury can oxidize extracellular matrix, increasing mesangial cell apoptosis. This oxidation impairs cell survival signaling, affecting transcription factors and MAPK pathways.
Area of Science:
- Nephrology
- Cell Biology
- Biochemistry
Background:
- Inflammatory kidney injury can lead to oxidation of extracellular matrix (ECM) proteins.
- Oxidized ECM may impair glomerular mesangial cell adhesion and intracellular signaling pathways.
Purpose of the Study:
- To investigate how ECM oxidation influences mesangial cell apoptosis.
- To determine the effect of ECM oxidation on the activity of Nuclear Factor-kappaB (NF-kappaB) and Mitogen-Activated Protein Kinase (MAPK) family members (ERK-1,2 and JNK).
Main Methods:
- Mesangial cells were cultured on oxidized and unmodified ECM.
- Apoptosis was quantified.
- Western blot analysis was used to assess levels of phosphorylated ERK-1,2, JNK, and NF-kappaB p65 subunit translocation.
Main Results:
- Exposure to oxidized ECM significantly increased mesangial cell apoptosis.
- Phosphorylated ERK-1,2 levels decreased, while phosphorylated JNK levels increased on oxidized ECM.
- Nuclear translocation of NF-kappaB p65 subunit was reduced in cells cultured on oxidized ECM.
Conclusions:
- ECM oxidation negatively impacts mesangial cell survival.
- Altered signaling pathways, including decreased pERK-1,2, increased pJNK, and diminished NF-kappaB activity, are associated with ECM oxidation in kidney injury.