title: [MnCl2-induced functional damage of mitochondria in human lung cells in vitro].
abstract: OBJECTIVE
  To explore the effect of MnCl(2) on the mitochondrial function of human lung cells, and to study the changes of protein expression level of nuclear respiratory factor-1 (NRF-1) in mitochondrial dysfunction induced by MnCl(2).
  
  
  METHODS
  The effects of MnCl(2) on cell survival rate were assessed by the reductions of tetrazolium dye (MTT) in cultured cell lines 16HBE and A549 cells. All tested16HBE and A549 cells were incubated with different concentrations of MnCl(2). The permeability transition pore (PTP) of mitochondria, mitochondrial membrane potential and the inhibition rate of mitochondrial enzymes as indicators of mitochondrial damage were measured by fluorescent spectrometry and MTT assay, respectively. Apoptosis was determined by flow cytometry. Protein levels of NRF-1 and mtTFA were measured by Western blot assay.
  
  
  RESULTS
  MnCl(2) decreased the survival rate of the two cell lines. The IC(50) of 16HBE and A549 cells were 1.91 mmol/L and 1.98 mmol/L, respectively. MnCl(2) caused a concentration-dependent decrease of mitochondrial enzymes and the inhibition rate of mitochondrial enzymes of the two cell lines induced by 1.00 mmol/L MnCl(2) were (52.8 ± 5.4)% and (50.6 ± 2.2)%, respectively. The PTP opening increased in MnCl(2)-treated cells in a dose- and time-dependent manner. Compared with the control group, mitochondrial membrane potential in the two cell lines was decreased by MnCl(2), by (7.9 ± 3.0)%, (26.2 ± 2.2)% and (27.8 ± 4.1)% in the 16HBE cells, and (4.7 ± 1.0)%, (14.9 ± 2.4)% and (27.5 ± 1.2)% in the A549 cells. Increased apoptosis rates of the two cell lines were induced by 1.00 mmol/L MnCl(2), (12.3 ± 1.9)% and (6.0 ± 0.4)%, respectively. The results of Western blot assay revealed that the protein levels of NRF-1 and mtTFA were decreased in manganese-treated cells in a dose-dependent manner, with a significant difference compared with that of the control cells (P < 0.05).
  
  
  CONCLUSIONS
  MnCl(2) induces mitochondrial dysfunction in 16HBE and A549 cells, and decreases the expression level of nuclear respiratory factor-1 (NRF-1), indicating that NRF-1 may play an important role in mitochondrial dysfunction.
authors.affiliation: Department of Preventive Medicine, Tongji University, Shanghai 200092, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Bao
authors.forename: Jue
authors.initials: J
authors.lastname: Li
authors.forename: Li-juan
authors.initials: LJ
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001980:Bronchi / Q000166:cytology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002712:Chlorides / Q000008:administration & dosage / Q000633:toxicity*; D004268:DNA-Binding Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D017895:Manganese Compounds / Q000008:administration & dosage; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology; D033681:Mitochondrial Membrane Transport Proteins / Q000187:drug effects; D000083162:Mitochondrial Permeability Transition Pore; D024101:Mitochondrial Proteins / Q000378:metabolism; D051266:Nuclear Respiratory Factor 1 / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D002712:Chlorides; D004268:DNA-Binding Proteins; D017895:Manganese Compounds; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D024101:Mitochondrial Proteins; C495633:NRF1 protein, human; D051266:Nuclear Respiratory Factor 1; C499631:TFAM protein, human; D014157:Transcription Factors; C025340:manganese chloride