title: Calcium-induced alteration of mitochondrial morphology and mitochondrial-endoplasmic reticulum contacts in rat brown adipocytes.
abstract: Mitochondria are key organelles maintaining cellular bioenergetics and integrity, and their regulation of [Ca2+]i homeostasis has been investigated in many cell types. We investigated the short-term Ca-SANDOZ® treatment on brown adipocyte mitochondria, using imaging and molecular biology techniques. Two-month-old male Wistar rats were divided into two groups: Ca-SANDOZ® drinking or tap water (control) drinking for three days. Alizarin Red S staining showed increased Ca2+ level in the brown adipocytes of treated rats, and potassium pyroantimonate staining localized electron-dense regions in the cytoplasm, mitochondria and around lipid droplets. Ca-SANDOZ® decreased mitochondrial number, but increased their size and mitochondrial cristae volume. Transmission electron microscopy revealed numerous enlarged and fusioned-like mitochondria in the Ca-SANDOZ® treated group compared to the control, and megamitochondria in some brown adipocytes. The Ca2+ diet affected mitochondrial fusion as mitofusin 1 (MFN1) and mitofusin 2 (MFN2) were increased, and mitochondrial fission as dynamin related protein 1 (DRP1) was decreased. Confocal microscopy showed a higher colocalization rate between functional mitochondria and endoplasmic reticulum (ER). The level of uncoupling protein-1 (UCP1) was elevated, which was confirmed by immunohistochemistry and Western blot analysis. These results suggest that Ca-SANDOZ® stimulates mitochondrial fusion, increases mitochondrial-ER contacts and the thermogenic capacity of brown adipocytes.
authors.affiliation: University of Belgrade. igo@bio.bg.ac.rs.
authors.forename: I
authors.initials: I
authors.lastname: Golic
authors.forename: K
authors.initials: K
authors.lastname: Velickovic
authors.forename: M
authors.initials: M
authors.lastname: Markelic
authors.forename: A
authors.initials: A
authors.lastname: Stancic
authors.forename: A
authors.initials: A
authors.lastname: Jankovic
authors.forename: M
authors.initials: M
authors.lastname: Vucetic
authors.forename: V
authors.initials: V
authors.lastname: Otasevic
authors.forename: B
authors.initials: B
authors.lastname: Buzadzic
authors.forename: B
authors.initials: B
authors.lastname: Korac
authors.forename: A
authors.initials: A
authors.lastname: Korac
mesh_terms: D052437:Adipocytes, Brown / Q000187:drug effects*; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D004721:Endoplasmic Reticulum / Q000187:drug effects*; D007150:Immunohistochemistry; D008297:Male; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000187:drug effects*; D051381:Rats; D013194:Staining and Labeling
chemical_list: D002118:Calcium