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Meprins cleave OS‐9 present in mouse kidneys subjected to ischemia reperfusion acute kidney injury
Author(s) -
Conley Sabena,
Martin Barry,
Ongeri Elimelda Moige
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.705.7
Subject(s) - microbiology and biotechnology , kidney , chemistry , western blot , biology , biochemistry , endocrinology , gene
Meprins, metalloproteinases that are highly expressed in the brush border membranes of proximal kidney tubules have been shown to intensify renal injury in ischemia reperfusion (IR). Osteosarcoma‐9 (OS‐9) has been shown to interact with meprin β and the hypoxia inducible factor, HIF‐1α, suggesting a role for OS‐9 in the hypoxia response. However, it's not known if OS‐9 is a meprin substrate. The objective of this study was to determine if OS‐9 is a meprin substrate, and whether this interaction is significant in the hypoxia response in vitro and in vivo. Hypoxia was induced in human embryonic kidney cells (HEK293) transfected with meprin α or meprin β cDNA by exposure to cobalt chloride. Western blot analysis was used to determine the levels of HIF‐1α and OS‐9 in cytosolic‐, nuclear‐ and membrane‐enriched fractions. To determine if OS‐9 is a meprin substrate, purified OS‐9 was incubated with activated forms of homomeric meprin A (α‐α) and meprin B (β‐β). Fragmentation of OS‐9 in the kidney proteins from wild‐type and meprin knockout mice subjected to IR was also evaluated by Western blot. OS‐9 was degraded by meprin B, but not homomeric meprin A. Stabilization of nuclear HIF‐1α was observed in cobalt chloride treated cells, but there was no clear correlation between nuclear levels of HIF‐1α and OS‐9. Fragmentation of OS‐9 was observed in WT, but not meprin KO kidneys subjected to IR, suggesting in vivo degradation.