cytochrome-c-t and Hypertension--Pulmonary

Idiopathic Pulmonary arterial hypertension (IPAH) is characterized by the obstructive remodelling of pulmonary arteries, and a progressive elevation in pulmonary arterial pressure (PAP) with subsequent right-sided heart failure and dead. Hypoxia induces the expression of peroxisome proliferator activated receptor γ coactivator-1α (PGC-1α) which regulates oxidative metabolism and mitochondrial biogenesis. We have analysed the expression of PGC-1α, cytochrome C (CYTC), superoxide dismutase (SOD), the total antioxidant status (TAS) and the activity of glutathione peroxidase (GPX) in blood samples of IPAH patients. Expression of PGC-1α was detected in IPAH patients but not in healthy volunteers. The mRNA levels of SOD were lower in IPAH patients compared to controls (3.93 ± 0.89 fold change). TAS and GPX activity were lower too in patients compared to healthy donors, (0.13 ± 0.027 versus 0.484 ± 0.048 mM and 56.034 ± 10.37 versus 165.46 ± 11.38 nmol/min/mL, resp.). We found a negative correlation between expression levels of PGC-1α and age, PAP and PVR, as well as a positive correlation with CI, PaO(2), mRNA levels of CYTC and SOD, TAS and GPX activity. These results taken together are indicative of the possible role of PGC-1α as a potential biomarker of the progression of IPAH.

Topics: Adult; Age Factors; Aged; Chlorides; Cytochromes c; Familial Primary Pulmonary Hypertension; Female; Glutathione Peroxidase; Heat-Shock Proteins; Humans; Hypertension, Pulmonary; Male; Middle Aged; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Superoxide Dismutase; Transcription Factors; Vascular Resistance

The objective of this paper was to investigate the contribution of mitochondrial ATP-sensitive K+ channel (mitoK(ATP)) and mitochondrial membrane potential (Deltapsim) to the distribution of cytochrome C in human pulmonary arterial smooth muscle cells (HPASMCs) and to the proliferation of HPASMCs induced by hypoxia. HPASMCs were divided into 6 groups, as following: (1) control group: cultured under normoxia; (2) diazoxide group: cultured in normoxia with diazoxide, an opener of mitoK(ATP); (3) 5-HD group: cultured in normoxia with 5-hydroxydecanoate (5-HD), an antagonist of mitoK(ATP); (4) 24-hour hypoxia group: cultured in hypoxia for 24 h; (5) 24-hour hypoxia + diazoxide group: cultured in hypoxia with diazoxide for 24 h; (6) 24-hour hypoxia + 5-HD group: cultured in hypoxia with 5-HD for 24 h. The relative changes in mitochondrial potential were tested with rhodamine fluorescence (R-123) technique. Western blot was used to detect the expression of cytochrome C protein in cell plasma and mitochondria,respectively. The expression of cell caspase-9 protein was determined with Western blot. The proliferation of HPASMCs was examined by cell cycle analysis and MTT colorimetric assay. The results were as following: after exposure to diazoxide for 24 h, the intensity of R-123 fluorescence in normoxic HPASMCs was significantly increased compared with that in the control group (P<0.05), but there was no significant change of the intensity of R-123 fluorescence after the HPASMCs had been exposed to 5-HD for 24 h; 24-hour hypoxia or 24-hour hypoxia + diazoxide could markedly increase the intensity of R-123 fluorescence in HPASMCs compared with normoxia (P<0.05), and the change was more significant in 24-hour hypoxia + diazoxide group than that in 24-hour hypoxia group (P<0.05); 5-HD could weaken the effect of 24-hour hypoxia on the intensity of R-123 fluorescence. After exposure to diazoxide for 24 h, the ratio of the expression of cytosolic cytochrome C protein to that of mitochondrial cytochrome C protein was significantly decreased compared with that in the control group (P<0.05), and the expression of caspase-9 protein was significantly decreased compared with that in the control group (P<0.05). The percentage of S phase and A value of MTT were significantly increased compared with those in the control group (P<0.05). But there were no significant changes in these tests after HPASMCs had been exposed to 5-HD for 24 h (P>0.05). After exposure to hypoxia or hypo

Topics: Cell Hypoxia; Cell Proliferation; Cells, Cultured; Cytochromes c; Humans; Hypertension, Pulmonary; Membrane Potential, Mitochondrial; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Potassium Channels; Pulmonary Artery; Signal Transduction

Germ line mutations in the bone morphogenetic protein (BMP) receptor type II (BMPRII) gene have been found in >50% of familial idiopathic pulmonary arterial hypertension (IPAH) patients and in 30% of sporadic cases of IPAH. Mutations of BMPRII occur in the extracellular ligand-binding domain, in the cytoplasmic serine/threonine kinase domain, or in the long carboxy terminus domain of unknown function. In this study, we demonstrate that BMPs promote apoptotic cell death in normal human pulmonary artery smooth muscle cells (PASMCs) by activation of caspases-3, -8, and -9, cytochrome c release, and downregulation of Bcl-2. Normal PASMCs expressing a kinase domain mutant or a carboxy-terminal domain deletion mutant of BMPRII identified in IPAH patients are resistant to BMP-mediated apoptosis. This dominant-negative effect may act in heterozygous patients and lead to the development of the pulmonary vascular medial hypertrophy found in IPAH patients. Our study also demonstrates an essential role of the carboxy terminus domain of BMPRII in the activation of the apoptotic signaling cascade.

Topics: Animals; Apoptosis; Bone Morphogenetic Protein 4; Bone Morphogenetic Protein 7; Bone Morphogenetic Protein Receptors, Type II; Bone Morphogenetic Proteins; Caspase 3; Caspase 8; Caspase 9; Cell Line, Tumor; Cells, Cultured; Curcuma; Cytochromes c; Down-Regulation; Enzyme Activation; Gene Deletion; Humans; Hypertension, Pulmonary; Mice; Muscle, Smooth, Vascular; Proto-Oncogene Proteins c-bcl-2; Pulmonary Artery; Signal Transduction; Transforming Growth Factor beta

Pulmonary arterial hypertension (PAH) is characterized by genetic and acquired abnormalities that suppress apoptosis and enhance cell proliferation in the vascular wall, including downregulation of the bone morphogenetic protein axis and voltage-gated K+ (Kv) channels. Survivin is an "inhibitor of apoptosis" protein, previously thought to be expressed primarily in cancer cells. We found that survivin was expressed in the pulmonary arteries (PAs) of 6 patients with PAH and rats with monocrotaline-induced PAH, but not in the PAs of 3 patients and rats without PAH. Gene therapy with inhalation of an adenovirus carrying a phosphorylation-deficient survivin mutant with dominant-negative properties reversed established monocrotaline-induced PAH and prolonged survival by 25%. The survivin mutant lowered pulmonary vascular resistance, RV hypertrophy, and PA medial hypertrophy. Both in vitro and in vivo, inhibition of survivin induced PA smooth muscle cell apoptosis, decreased proliferation, depolarized mitochondria, caused efflux of cytochrome c in the cytoplasm and translocation of apoptosis-inducing factor into the nucleus, and increased Kv channel current; the opposite effects were observed with gene transfer of WT survivin, both in vivo and in vitro. Inhibition of the inappropriate expression of survivin that accompanies human and experimental PAH is a novel therapeutic strategy that acts by inducing vascular mitochondria-dependent apoptosis.

Topics: Adenoviridae; Adult; Animals; Apoptosis; Cytochromes c; Disease Models, Animal; Female; Gene Expression; Genes, Dominant; Genetic Therapy; Humans; Hypertension, Pulmonary; Inhibitor of Apoptosis Proteins; Male; Microtubule-Associated Proteins; Middle Aged; Mitochondria; Muscle, Smooth, Vascular; Mutation; Neoplasm Proteins; Potassium Channels, Voltage-Gated; Pulmonary Artery; Rats; Rats, Sprague-Dawley; Survivin; Vascular Resistance

Patients with congestive heart failure (CHF) have decreased exercise capacity because of muscle fatigability. Symptoms are due to a specific myopathy with increased expression of fast type II fibres, fast MHCs and muscle atrophy. PGC-1alpha, a potent transcriptional coactivator for nuclear receptors, induces mitochondrial myogenesis and the preferential synthesis of slow fibres. IGF1-Calcineurin stimulation can lead to increased expression of PGC-1alpha.. We investigated the levels of PGC-1alpha during progression and regression of skeletal myopathy in the soleus muscle of rats with right heart failure secondary to monocrotaline-induced pulmonary hypertension. We used GH to stimulate the IGF1-calcineurin-PGC-1alpha axis.. The slow MHC1 decreased from 90.6+/-0.5 to 71.7+/-2.2 in the CHF rats (p<0.00001) and increased to 82.1+/-1.8 after GH (p<0.00002). Western blot analysis showed that PGC-1alpha is significantly decreased in CHF, while it came back to control values after GH. Cytochrome c was decreased in CHF and returned to control values with GH. Troponin I was expressed solely as slow isoform in the control soleus, while the fast isoform appeared in CHF. Its expression returned to control values after GH.. We conclude that PGC-1alpha plays an important role in regulating slow fibres expression. PGC1-1alpha is in turn regulated by the IGF1-calcineurin axis. GH by increasing the circulating levels of IGF1, enhanced the expression of slow MHC1, TnI and the synthesis of mitochondria.

Topics: Animals; Apoptosis; Blotting, Western; Calcineurin; Cytochromes c; Heart Failure; Heat-Shock Proteins; Human Growth Hormone; Hypertension, Pulmonary; Immunohistochemistry; Insulin-Like Growth Factor I; Male; Muscle Fibers, Skeletal; Muscle, Skeletal; Myosin Heavy Chains; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Protein Isoforms; Rats; Rats, Sprague-Dawley; Transcription Factors; Troponin I