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Updated: May 26, 2025
Renal Ischaemia Reperfusion Injury: A Mouse Model of Injury and Regeneration
Published on: June 7, 2014
Meprin β regulates osteopontin-signaling in ischemia/reperfusion-induced kidney injury
Faihaa Ahmed1,2, Shaymaa Abousaad1, Ayman Abouzeid3
1Department of Kinesiology, North Carolina A&T State University, Greensboro, NC, 27411, USA.
Background:
Meprin metalloproteases have been implicated in the pathology of ischemia/reperfusion (IR) induced kidney injury. Meprin β proteolytically processes several mediators of cell signaling pathways involved in apoptosis and extracellular matrix metabolism. We previously showed that meprin β cleaves osteopontin (OPN) in vitro. The objective of the current study was to determine how meprin β expression affects OPN and downstream mediators of the OPN-signaling pathway in IR-induced kidney injury.
Methods:
Ischemia/Reperfusion injury was induced in wild-type (WT) and meprin β knockout (βKO) mice. Blood samples and kidney tissues were obtained at 24 h post-IR. The levels of OPN, Caspase-3, Bcl-2, and NFκB were evaluated using real-time PCR, western blot, and immunohistochemical approaches. Data analysis utilized a combination of 2-way ANOVA and unpaired t test.
Results:
OPN mRNA increased in both genotypes at 24 h post-IR. Immunohistochemical staining showed IR-associated increases in the levels of OPN in both genotypes. Additionally, we observed higher levels of OPN in the lumen of proximal tubules in WT only, suggesting that meprin β contributes to enhanced release of OPN into filtrate and ultimately into urine. Immunohistochemical staining showed significant increases in the levels of Caspase-3 and NFκB in select tubules of WT only, while Bcl-2 staining intensity increased significantly in both genotypes at 24 h post-IR.
Conclusions:
These findings suggest that meprin β modulates OPN levels in IR-induced kidney injury and impacts apoptotic genes regulated by the OPN signaling pathway.
Clinical Trial Number:
Not applicable.
Insights
Meprin beta influences osteopontin (OPN) levels and related apoptosis pathways in kidney injury. Its absence alters OPN distribution and downstream signaling in ischemia/reperfusion injury models.
Area of Science:
- Nephrology
- Molecular Biology
- Pathology
Background:
- Meprin metalloproteases are implicated in kidney injury.
- Meprin beta processes signaling mediators involved in apoptosis and ECM metabolism.
- Meprin beta cleaves osteopontin (OPN).
Purpose of the Study:
- To determine how meprin beta expression affects OPN and downstream mediators in kidney injury.
- Investigate the role of meprin beta in the OPN signaling pathway during ischemia/reperfusion (IR).
Main Methods:
- Ischemia/Reperfusion (IR) injury induced in wild-type and meprin beta knockout mice.
- Quantification of OPN, Caspase-3, Bcl-2, and NFκB using PCR, western blot, and immunohistochemistry.
- Statistical analysis using 2-way ANOVA and unpaired t-tests.
Main Results:
- OPN mRNA and protein levels increased post-IR in both genotypes.
- Higher OPN levels in proximal tubule lumens of wild-type mice suggest meprin beta enhances OPN release into filtrate.
- Increased Caspase-3 and NFκB in wild-type tubules; Bcl-2 increased in both genotypes post-IR.
Conclusions:
- Meprin beta modulates OPN levels in IR-induced kidney injury.
- Meprin beta influences apoptotic genes regulated by the OPN signaling pathway.
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