The purpose of this paper was to study the transcriptional regulation of nuclear respiratory factor 1 (NRF1) on nuclear factor kappa B (NF-κB), a key molecule in lipopolysaccharide (LPS)-induced lung epithelial inflammation, and to clarify the mechanism of NRF1-mediated inflammatory response in lung epithelial cells. In vivo, male BALB/c mice were treated with NRF1 siRNA, followed with LPS (4 mg/kg) or 0.9% saline through respiratory tract, and sacrificed 48 h later. Expression levels of NRF1, NF-κB p65 and its target genes were detected by Western blot and real-time PCR. Nuclear translocation of NRF1 or p65 was measured by immunofluorescent technique. In vitro, L132 cells were transfected with NRF1 siRNA or treated with BAY 11-7082 (5 μmol/L) for 24 h, followed with treatment of 1 mg/L LPS for 6 h. Cells were lysed for detections of NRF1, NF-κB p65 and its target genes as well as the binding sites of NRF1 on RELA (encoding NF-κB p65) promoter by chromatin immunoprecipitation assay (ChIP). Results showed that LPS stimulated NRF1 and NF-κB p65. Pro-inflammatory factors including interleukin-1β (IL-1β) and IL-6 were significantly increased both in vivo and in vitro. Obvious nuclear translocations of NRF1 and p65 were observed in LPS-stimulated lung tissue. Silencing NRF1 resulted in a decrease of p65 and its target genes both in vivo and in vitro. In addition, BAY 11-7082, an inhibitor of NF-κB, significantly repressed the inflammatory responses induced by LPS without affecting NRF1 expression. Furthermore, it was proved that NRF1 had three binding sites on RELA promoter region. In summary, NRF1 is involved in LPS-mediated acute lung injury through the transcriptional regulation on NF-κB p65.
Acute Lung Injury/genetics* ; Animals ; Lipopolysaccharides/pharmacology* ; Male ; Mice ; NF-kappa B/metabolism* ; Nuclear Respiratory Factor 1/genetics* ; RNA, Small Interfering ; Transcription Factor RelA/metabolism*

OBJECTIVETo investigate the relationship between PPAR coactivator 1 (PGC-1), nuclear respiratory factor (NRF), mitochondrial transcription factor A (mtTFA) expressions of vascular smooth muscle cells (VSMC) and development of atherosclerosis in a rabbit model.

METHODSAtherosclerotic model was established by feeding the rabbits with high-fat diet for 4, 8 and 12 weeks (n = 10 each). Another 8 rabbits fed with normal diet served as normal controls. Intima-media ratio, mRNA and protein expressions of PGC-1, NRF, mtTFA and SMemb, a marker for synthetic VSMC, were detected on aorta specimens.

RESULTSWith the blood lipid increased, the intima-media ratio rose from (0.031 +/- 0.010) microm up to (0.814 +/- 0.258) microm during 12 weeks. Increasing SMemb means that synthetic VSMC grew more and more. The expressions of PGC-1 became significant after 4 weeks (P < 0.01), while that of NRF-1 and mtTFA rose significantly after 8 weeks (P < 0.01).

CONCLUSIONSThe PGC-NRF-mtTFA pathway might play a critical role in VSMC proliferation and development of atherosclerosis.

Animals ; Atherosclerosis ; blood ; metabolism ; pathology ; DNA-Binding Proteins ; metabolism ; Disease Models, Animal ; Female ; Lipids ; blood ; Male ; Mitochondrial Proteins ; metabolism ; Muscle, Smooth, Vascular ; metabolism ; Nuclear Respiratory Factor 1 ; metabolism ; Rabbits ; Trans-Activators ; metabolism ; Transcription Factors ; metabolism

BACKGROUND/OBJECTIVES: The study was conducted to evaluate the effects of dietary leucine supplementation on mitochondrial biogenesis and energy metabolism in the liver of normal birth weight (NBW) and intrauterine growth-retarded (IUGR) weanling piglets. MATERIALS/METHODS: A total of sixteen pairs of NBW and IUGR piglets from sixteen sows were selected according to their birth weight. At postnatal day 14, all piglets were weaned and fed either a control diet or a leucine-supplemented diet for 21 d. Thereafter, a 2 × 2 factorial experimental design was used. Each treatment consisted of eight replications with one piglet per replication. RESULTS: Compared with NBW piglets, IUGR piglets had a decreased (P < 0.05) hepatic adenosine triphosphate (ATP) content. Also, IUGR piglets exhibited reductions (P < 0.05) in the activities of hepatic mitochondrial pyruvate dehydrogenase (PDH), citrate synthase (CS), α-ketoglutarate dehydrogenase (α-KGDH), malate dehydrogenase (MDH), and complexes I and V, along with decreases (P < 0.05) in the concentration of mitochondrial DNA (mtDNA) and the protein expression of hepatic peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α). Dietary leucine supplementation increased (P < 0.05) the content of ATP, and the activities of CS, α-KGDH, MDH, and complex V in the liver of piglets. Furthermore, compared to those fed a control diet, piglets given a leucine-supplemented diet exhibited increases (P < 0.05) in the mtDNA content and in the mRNA expressions of sirtuin 1, PGC-1α, nuclear respiratory factor 1, mitochondrial transcription factor A, and ATP synthase, H+ transporting, mitochondrial F1 complex, β polypeptide in liver. CONCLUSIONS: Dietary leucine supplementation may exert beneficial effects on mitochondrial biogenesis and energy metabolism in NBW and IUGR weanling piglets.
Adenosine Triphosphate ; Birth Weight* ; Citrate (si)-Synthase ; Diet ; DNA, Mitochondrial ; Energy Metabolism* ; Fetal Growth Retardation ; Leucine* ; Liver ; Malate Dehydrogenase ; Nuclear Respiratory Factor 1 ; Organelle Biogenesis* ; Oxidoreductases ; Parturition* ; Peroxisomes ; Pyruvic Acid ; Research Design ; RNA, Messenger ; Sirtuin 1 ; Transcription Factors

OBJECTIVE: To explore the protective effect and underlying mechanism of Lycium barbarum polysaccharides (LBP) in a non-alcoholic fatty liver disease (NAFLD) cell model. METHODS: Normal human hepatocyte LO2 cells were treated with 1 mmol/L free fatty acids (FFA) mixture for 24 h to induce NAFLD cell model. Cells were divided into 5 groups, including control, model, low-, medium- and high dose LBP (30,100 and 300 µg/mL) groups. The monosaccharide components of LBP were analyzed with high performance liquid chromatography. Effects of LBP on cell viability and intracellular lipid accumulation were assessed by cell counting Kit-8 assay and oil red O staining, respectively. Triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), adenosine triphosphate (ATP) and oxidative stress indicators were evaluated. Energy balance and mitochondrial biogenesis related mRNA and proteins were determined by quantitative real-time polymerase chain reaction and Western blot, respectively. RESULTS: Heteropolysaccharides with mannose and glucose are the main components of LBP. LBP treatment significantly decreased intracellular lipid accumulation as well as TG, ALT, AST and malondialdehyde levels (P<0.05 or P<0.01), increased the levels of superoxide dismutase, phospholipid hydroperoxide glutathione peroxidase, catalase, and ATP in NAFLD cell model (P<0.05). Meanwhile, the expression of uncoupling protein 2 was down-regulated and peroxisome proliferator-activated receptor gamma coactivator-1α/nuclear respiratory factor 1/mitochondrial transcription factor A pathway was up-regulated (P<0.05). CONCLUSION LBP promotes mitochondrial biogenesis and improves energy balance in NAFLD cell model.
Humans ; Non-alcoholic Fatty Liver Disease/drug therapy* ; Lycium/metabolism* ; Catalase/metabolism* ; Organelle Biogenesis ; Alanine Transaminase ; Uncoupling Protein 2 ; Fatty Acids, Nonesterified ; Mannose ; Nuclear Respiratory Factor 1/metabolism* ; PPAR gamma/metabolism* ; Phospholipid Hydroperoxide Glutathione Peroxidase ; Drugs, Chinese Herbal/pharmacology* ; Malondialdehyde/metabolism* ; Superoxide Dismutase/metabolism* ; Polysaccharides/pharmacology* ; Triglycerides ; RNA, Messenger ; Aspartate Aminotransferases ; Glucose ; Adenosine Triphosphate

Mitochondrial dysfunction and endoplasmic reticulum (ER) stress are considered the key determinants of insulin resistance. Impaired mitochondrial function in obese animals was shown to induce the ER stress response, resulting in reduced adiponectin synthesis in adipocytes. The expression of inducible nitric oxide synthase (iNOS) is increased in adipose tissues in genetic and dietary models of obesity. In this study, we examined whether activation of iNOS is responsible for palmitate-induced mitochondrial dysfunction, ER stress, and decreased adiponectin synthesis in 3T3L1 adipocytes. As expected, palmitate increased the expression levels of iNOS and ER stress response markers, and decreased mitochondrial contents. Treatment with iNOS inhibitor increased adiponectin synthesis and reversed the palmitate-induced ER stress response. However, the iNOS inhibitor did not affect the palmitate-induced decrease in mitochondrial contents. Chemicals that inhibit mitochondrial function increased iNOS expression and the ER stress response, whereas measures that increase mitochondrial biogenesis (rosiglitazone and adenoviral overexpression of nuclear respiratory factor-1) reversed them. Inhibition of mitochondrial biogenesis prevented the rosiglitazone-induced decrease in iNOS expression and increase in adiponectin synthesis. These results suggest that palmitate-induced mitochondrial dysfunction is the primary event that leads to iNOS induction, ER stress, and decreased adiponectin synthesis in cultured adipocytes.
3T3-L1 Cells ; *Adipocytes/drug effects/metabolism ; Adiponectin/biosynthesis ; Adipose Tissue/metabolism ; Animals ; Endoplasmic Reticulum Stress/drug effects ; Insulin Resistance/genetics ; Mice ; Mitochondria/drug effects/*metabolism/pathology ; Mitochondrial Turnover/drug effects/genetics ; *Nitric Oxide Synthase Type II/genetics/metabolism ; Nuclear Respiratory Factor 1 ; Obesity/genetics/metabolism ; Palmitic Acid/pharmacology ; Thiazolidinediones/pharmacology

OBJECTIVETo 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).

METHODSThe 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.

RESULTSMnCl(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).

CONCLUSIONMnCl(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.

Apoptosis ; drug effects ; Bronchi ; cytology ; Cell Line, Tumor ; Cell Survival ; drug effects ; Cells, Cultured ; Chlorides ; administration & dosage ; toxicity ; DNA-Binding Proteins ; metabolism ; Dose-Response Relationship, Drug ; Epithelial Cells ; cytology ; metabolism ; Humans ; Lung Neoplasms ; metabolism ; pathology ; Manganese Compounds ; administration & dosage ; Membrane Potential, Mitochondrial ; drug effects ; Mitochondria ; drug effects ; physiology ; Mitochondrial Membrane Transport Proteins ; drug effects ; Mitochondrial Proteins ; metabolism ; Nuclear Respiratory Factor 1 ; metabolism ; Transcription Factors ; metabolism