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An Efficient Sieving Method to Isolate Intact Glomeruli from Adult Rat Kidney
Published on: November 1, 2018
Metalloprotease meprin beta in rat kidney: glomerular localization and differential expression in glomerulonephritis
Beatrice Oneda1, Nadège Lods, Daniel Lottaz
1Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
Abstract:
Meprin (EC 3.4.24.18) is an oligomeric metalloendopeptidase found in microvillar membranes of kidney proximal tubular epithelial cells. Here, we present the first report on the expression of meprin beta in rat glomerular epithelial cells and suggest a potential involvement in experimental glomerular disease. We detected meprin beta in glomeruli of immunostained rat kidney sections on the protein level and by quantitative RT-PCR of laser-capture microdissected glomeruli on the mRNA level. Using immuno-gold staining we identified the membrane of podocyte foot processes as the main site of meprin beta expression. The glomerular meprin beta expression pattern was altered in anti-Thy 1.1 and passive Heymann nephritis (PHN). In addition, the meprin beta staining pattern in the latter was reminiscent of immunostaining with the sheep anti-Fx1A antiserum, commonly used in PHN induction. Using Western blot and immunoprecipitation assays we demonstrated that meprin beta is recognized by Fx1A antiserum and may therefore represent an auto-antigen in PHN. In anti-Thy 1.1 glomerulonephritis we observed a striking redistribution of meprin beta in tubular epithelial cells from the apical to the basolateral side and the cytosol. This might point to an involvement of meprin beta in this form of glomerulonephritis.
Insights
Meprin beta, a kidney enzyme, is newly found in rat glomerular cells and podocyte foot processes. Its expression changes in experimental kidney diseases, suggesting a role in glomerular injury.
Area of Science:
- Nephrology
- Molecular Biology
- Enzymology
Background:
- Meprin (EC 3.4.24.18) is an oligomeric metalloendopeptidase typically located in the microvillar membranes of kidney proximal tubular epithelial cells.
- Its presence and function in glomerular epithelial cells, particularly podocytes, remain largely uncharacterized.
Purpose of the Study:
- To investigate the expression and localization of meprin beta in rat glomerular epithelial cells.
- To explore the potential involvement of meprin beta in the pathogenesis of experimental glomerular diseases, specifically anti-Thy 1.1 glomerulonephritis and passive Heymann nephritis (PHN).
Main Methods:
- Immunohistochemistry and immuno-gold staining on rat kidney sections to detect meprin beta protein.
- Quantitative reverse transcription-polymerase chain reaction (RT-PCR) on laser-capture microdissected glomeruli for mRNA analysis.
- Western blot and immunoprecipitation assays to assess antigenicity.
Main Results:
- Meprin beta was detected in rat glomeruli at both protein and mRNA levels, primarily localized to podocyte foot processes.
- Glomerular meprin beta expression patterns were significantly altered in both anti-Thy 1.1 glomerulonephritis and passive Heymann nephritis models.
- Meprin beta was recognized by Fx1A antiserum, indicating it may be an auto-antigen in PHN.
- In anti-Thy 1.1 glomerulonephritis, meprin beta redistributed within tubular epithelial cells.
Conclusions:
- Meprin beta is expressed in rat glomerular epithelial cells, particularly podocytes, and its expression is modulated during experimental glomerular injury.
- These findings suggest a potential role for meprin beta in the development or progression of glomerular diseases.
- Meprin beta may act as an auto-antigen in passive Heymann nephritis and is redistributed in tubular cells during anti-Thy 1.1 glomerulonephritis, highlighting its dynamic involvement in kidney pathology.
