title: The predominant pathway of apoptosis in THP-1 macrophage-derived foam cells induced by 5-aminolevulinic acid-mediated sonodynamic therapy is the mitochondria-caspase pathway despite the participation of endoplasmic reticulum stress.
abstract: BACKGROUND
  In advanced atherosclerosis, chronic endoplasmic reticulum (ER) stress induces foam cells apoptosis and generates inflammatory reactions.
  
  
  METHODS
  THP-1 macrophage-derived foam cells (FC) were incubated with 1 mM 5-aminolevulinic acid (ALA). After ALA mediated sonodynamic therapy (ALA-SDT), apoptosis of FC was assayed by Annexin V-PI staining. Intracellular reactive oxygen species (ROS) and mitochondrial membrane potential were detected by staining with CellROX® Green Reagent and jc-1. Pretreatment of FC with N-acetylcysteine (NAC), Z-VAD-FMK or 4-phenylbutyrate (4-PBA), mitochondria apoptotic pathway associated proteins and C/EBP-homologous (CHOP) expressions were assayed by wertern blotting.
  
  
  RESULTS
  Burst of apoptosis of FC was observed at 5-hour after ALA-SDT with 6-hour incubation of ALA and 0.4 W/cm(2) ultrasound. After ALA-SDT, intracellular ROS level increased and mitochondrial membrane potential collapsed. Translocations of cytochrome c from mitochondria into cytosol and Bax from cytosol into mitochondria, cleaved caspase 9, cleaved caspase 3, upregulation of CHOP, as well as downregulation of Bcl-2 after ALA-SDT were detected, which could be suppressed by NAC. Activation of mitochondria-caspase pathway could not be inhibited by 4-PBA. Cleaved caspase 9 and caspase 3 as well as apoptosis induced by ALA-SDT could be inhibited by Z-VAD-FMK.
  
  
  CONCLUSIONS
  The mitochondria-caspase pathway is predominant in the apoptosis of FC induced by ALA-SDT though ER stress participates in.
authors.affiliation: Division of Cardiology, the First Affiliated Hospital, Cardiovascular Institute, Harbin Medical University, Harbin, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Haibo
authors.initials: H
authors.lastname: Chen
authors.forename: Juhua
authors.initials: J
authors.lastname: Dan
authors.forename: Jiali
authors.initials: J
authors.lastname: Cheng
authors.forename: Shuyuan
authors.initials: S
authors.lastname: Guo
authors.forename: Xin
authors.initials: X
authors.lastname: Sun
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Yiwei
authors.initials: Y
authors.lastname: Ai
authors.forename: Shuchang
authors.initials: S
authors.lastname: Li
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Peng
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tian
authors.forename: Liming
authors.initials: L
authors.lastname: Yang
authors.forename: Jichao
authors.initials: J
authors.lastname: Wu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhong
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhou
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Zhang
authors.forename: Wenwu
authors.initials: W
authors.lastname: Cao
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
mesh_terms: D000622:Aminolevulinic Acid / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D005487:Foam Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D021381:Protein Transport / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013010:Sonication / Q000295:instrumentation; D014464:Ultrasonic Therapy / Q000295:instrumentation; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D000622:Aminolevulinic Acid; D045304:Cytochromes c; D020169:Caspases