title: Macrophage mitochondrial damage from StAR transport of 7-hydroperoxycholesterol: implications for oxidative stress-impaired reverse cholesterol transport.
abstract: StAR family proteins in vascular macrophages participate in reverse cholesterol transport (RCT). We hypothesize that under pathophysiological oxidative stress, StARs will transport not only cholesterol to macrophage mitochondria, but also pro-oxidant cholesterol hydroperoxides (7-OOHs), thereby impairing early-stage RCT. Upon stimulation with dibutyryl-cAMP, RAW264.7 macrophages exhibited a strong time-dependent induction of mitochondrial StarD1 and plasma membrane ABCA1, which exports cholesterol. 7α-OOH uptake by stimulated RAW cell mitochondria (like cholesterol uptake) was strongly reduced by StarD1 knockdown, consistent with StarD1 involvement. Upon uptake by mitochondria, 7α-OOH (but not redox-inactive 7α-OH) triggered lipid peroxidation and membrane depolarization while reducing ABCA1 upregulation. These findings provide strong initial support for our hypothesis.
authors.affiliation: Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Biophysics, Jagiellonian University, Krakow, Poland. Electronic address: witekkor@mcw.edu.
authors.forename: Witold
authors.initials: W
authors.lastname: Korytowski
authors.affiliation: Department of Biophysics, Jagiellonian University, Krakow, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Wawak
authors.affiliation: Department of Biophysics, Jagiellonian University, Krakow, Poland.
authors.forename: Pawel
authors.initials: P
authors.lastname: Pabisz
authors.affiliation: Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA.
authors.forename: Jared C
authors.initials: JC
authors.lastname: Schmitt
authors.affiliation: Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA.
authors.forename: Albert W
authors.initials: AW
authors.lastname: Girotti
mesh_terms: D064286:ATP Binding Cassette Transporter 1 / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D015153:Blotting, Western; D003994:Bucladesine / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D015227:Lipid Peroxidation / Q000187:drug effects; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000378:metabolism*; D018384:Oxidative Stress; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D013997:Time Factors; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D064286:ATP Binding Cassette Transporter 1; D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; C041011:cholesterol 7-hydroperoxide; D003994:Bucladesine; D002784:Cholesterol
keywords: 1-palmitoyl-2-sn-glycero-3-phosphocholine; 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide; 3β-hydroxycholest-5-ene-7α-hydroperoxide; 4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-inda-cene-3-undecanoic acid; 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethyl-benzimidazolylcarbocyanine iodide; 7α-OH; 7α-OOH; ABCA1; ATP binding cassette transporter A1; C11-BODIPY; ChOOH(s); Cholesterol hydroperoxide; JC-1; MTT; Macrophage; Oxidative stress; PBS; POPC; Reverse cholesterol transport; SUV(s); StAR protein; StarD1; StarD4; cholest-5-ene-3β,7α-diol; cholesterol hydroperoxide(s); db-cAMP; dibutyryl-cAMP; phosphate-buffered saline; small unilamellar vesicle(s); type-1 steroidogenic acute regulatory domain protein; type-4 steroidogenic acute regulatory domain protein