Presentation Title

Delivering copper from hemopexin to mammary epithelial and hepatic cells

Faculty Mentor

Theodros Z. Kidane ,Maria C. Linder

Start Date

23-11-2019 8:45 AM

End Date

23-11-2019 9:30 AM

Location

52

Session

poster 2

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Copper is a critical trace element in mammalian metabolism due to its involvement as a cofactor for enzymes involved in redox reactions. So far, our lab has found that copper can be delivered to cells by albumin, transcuprein, and ceruloplasmin in the blood fluid. Hemopexin is a plasma protein, which can bind to copper and also has the highest binding affinity to heme among other proteins. Hemopexin plays an important role in mammalian metabolism because it participates in bringing iron in heme back to the liver so it can be reused for hemoglobin production. In this research project, we explore the involvement of hemopexin in the process of delivering radioactive copper tracer to mammary epithelial and hepatic cells as well as the potential interference of copper with the binding of heme to hemopexin and vice versa. The objective is to test whether mammary epithelial cells take up copper bound to hemopexin or not and investigate how the process takes place, including whether copper enters cells through copper transporters or through receptor-mediated endocytosis, and whether heme binding makes a difference. Confluent cells were first pretreated with and without endocytosis inhibitors (Dynasore, Nocodazole, Pitstop), followed by incubation with 67Cu-labeled pure human hemopexin for 3 hours before uptake was stopped, cells were washed and lysed, and cell radioactivity was measured in a gamma counter. Uptake was calculated as percent dose per h per mg cell protein. The results showed that copper was taken up from hemopexin by both cell types, but in the mammary epithelial cells this process may not be occurring via endocytosis. In contrast, some of the copper taken up by hepatic cells may involve endocytosis.

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Nov 23rd, 8:45 AM Nov 23rd, 9:30 AM

Delivering copper from hemopexin to mammary epithelial and hepatic cells

52

Copper is a critical trace element in mammalian metabolism due to its involvement as a cofactor for enzymes involved in redox reactions. So far, our lab has found that copper can be delivered to cells by albumin, transcuprein, and ceruloplasmin in the blood fluid. Hemopexin is a plasma protein, which can bind to copper and also has the highest binding affinity to heme among other proteins. Hemopexin plays an important role in mammalian metabolism because it participates in bringing iron in heme back to the liver so it can be reused for hemoglobin production. In this research project, we explore the involvement of hemopexin in the process of delivering radioactive copper tracer to mammary epithelial and hepatic cells as well as the potential interference of copper with the binding of heme to hemopexin and vice versa. The objective is to test whether mammary epithelial cells take up copper bound to hemopexin or not and investigate how the process takes place, including whether copper enters cells through copper transporters or through receptor-mediated endocytosis, and whether heme binding makes a difference. Confluent cells were first pretreated with and without endocytosis inhibitors (Dynasore, Nocodazole, Pitstop), followed by incubation with 67Cu-labeled pure human hemopexin for 3 hours before uptake was stopped, cells were washed and lysed, and cell radioactivity was measured in a gamma counter. Uptake was calculated as percent dose per h per mg cell protein. The results showed that copper was taken up from hemopexin by both cell types, but in the mammary epithelial cells this process may not be occurring via endocytosis. In contrast, some of the copper taken up by hepatic cells may involve endocytosis.