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Transient and sequential expression of chemokine mRNA in glomeruli in puromycin aminonucleoside nephrosis
1Department of Clinical Pharmacology, Research Institute, International Medical Center of Japan, Tokyo, Japan.
Abstract:
Chemokines are a large family of low-molecular-weight proinflammatory cytokines that stimulate recruitment of leukocytes. We previously reported that among six chemokines, the expression of mRNAs for MCP-1, MCP-3, TCA3, and MIP-1alpha, but not for MIP-1beta and RANTES, was markedly elevated in the renal cortex of rats with puromycin aminonucleoside induced nephrosis. In this study we have determined the glomerular expression of the chemokine mRNAs in this model using quantitative competitive reverse-transcriptase polymerase chain reaction. After an injection of puromycin aminonucleoside, the number of monocytes/macrophages and CD4+ and CD8+ cells markedly increased by day 5 and increased thereafter until day 10. The levels of mRNAs for MCP-1, MCP-3, and lymphotactin increased on day 5 and returned to their normal levels by day 7. The level of TCA3 mRNA increased on day 3, and that of MIP-1alpha mRNA increased on day 7, but both returned to their normal levels within 2 days. No increase in the mRNAs of MIP-1beta or RANTES was observed until day 10. These results indicate that the expression pattern of the chemokine mRNAs in glomeruli resembles that in renal cortex, but is more transient and sequential.
Insights
Chemokine mRNA expression in rat glomeruli changes rapidly during puromycin aminonucleoside-induced nephrosis. Glomerular chemokine mRNA levels show a transient and sequential pattern, distinct from renal cortex expression.
Area of Science:
- Nephrology
- Immunology
- Molecular Biology
Background:
- Chemokines are key regulators of leukocyte recruitment in inflammatory conditions.
- Puromycin aminonucleoside (PAN) nephrosis is a model for studying kidney injury and inflammation.
- Previous studies showed elevated renal cortex chemokine mRNA in PAN nephrosis.
Purpose of the Study:
- To investigate the glomerular expression of specific chemokine mRNAs in PAN-induced nephrosis.
- To compare glomerular chemokine mRNA expression patterns with those in the renal cortex.
- To correlate chemokine mRNA expression with leukocyte infiltration in the glomeruli.
Main Methods:
- Induction of nephrosis in rats using puromycin aminonucleoside.
- Quantitative competitive reverse-transcriptase polymerase chain reaction (QC-RT-PCR) for chemokine mRNA analysis.
- Immunohistochemistry to assess leukocyte infiltration (monocytes/macrophages, CD4+, CD8+ cells).
Main Results:
- Leukocyte infiltration increased significantly in glomeruli by day 5 post-PAN injection.
- mRNA levels for MCP-1, MCP-3, and lymphotactin peaked on day 5 and normalized by day 7.
- TCA3 and MIP-1alpha mRNA levels showed transient increases on days 3 and 7, respectively.
- MIP-1beta and RANTES mRNA levels did not increase until day 10.
Conclusions:
- Glomerular chemokine mRNA expression in PAN nephrosis follows a transient and sequential pattern.
- This glomerular expression pattern differs from the more sustained renal cortex expression.
- Chemokine dynamics in glomeruli are crucial for understanding leukocyte recruitment in kidney injury.