ABSTRACT
The development of right heart failure (RHF) is characterized by alterations of right ventricle (RV) structure and function, but the mechanisms of RHF remain still unknown. Thus, understanding the RHF is essential for improved therapies. Therefore, identification by quantitative proteomics of targets specific to RHF may have therapeutic benefits to identify novel potential therapeutic targets. The objective of this study was to analyze the molecular mechanisms changing RV function in the diseased RHF and thus, to identify novel potential therapeutic targets. For this, we have performed differential proteomic analysis of whole RV proteins using two experimental rat models of RHF. Differential protein expression was observed for hundred twenty six RV proteins including proteins involved in structural constituent of cytoskeleton, motor activity, structural molecule activity, cytoskeleton protein binding and microtubule binding. Interestingly, further analysis of down-regulated proteins, reveals that both protein and gene expressions of proteasome subunits were drastically decreased in RHF, which was accompanied by an increase of ubiquitinated proteins. Interestingly, the proteasomal activities chymotrypsin and caspase-like were decreased whereas trypsin-like activity was maintained. In conclusion, this study revealed the involvement of ubiquitin-proteasome system (UPS) in RHF. Three deregulated mechanisms were discovered: (1) decreased gene and protein expressions of proteasome subunits, (2) decreased specific activity of proteasome; and (3) a specific accumulation of ubiquitinated proteins. This modulation of UPS of RV may provide a novel therapeutic avenue for restoration of cardiac function in the diseased RHF.
Subject(s)
Heart Failure/genetics , Heart Ventricles/metabolism , Hypoxia/genetics , Proteasome Endopeptidase Complex/chemistry , Proteome/genetics , Ventricular Dysfunction, Right/genetics , Animals , Gene Expression Profiling , Gene Expression Regulation , Heart Failure/chemically induced , Heart Failure/metabolism , Heart Failure/pathology , Heart Ventricles/pathology , Hypoxia/metabolism , Hypoxia/pathology , Male , Monocrotaline , Proteasome Endopeptidase Complex/genetics , Proteasome Endopeptidase Complex/metabolism , Proteolysis , Proteome/metabolism , Rats , Rats, Wistar , Signal Transduction , Ubiquitination , Ventricular Dysfunction, Right/chemically induced , Ventricular Dysfunction, Right/metabolism , Ventricular Dysfunction, Right/pathologyABSTRACT
Tetrahydrobiopterin (BH4), which fosters the formation of and stabilizes endothelial NO synthase (eNOS) as an active dimer, tightly regulates eNOS coupling / uncoupling. Moreover, studies conducted in genetically-modified models demonstrate that BH4 pulmonary deficiency is a key determinant in the pathogenesis of pulmonary hypertension. The present study thus investigates biopterin metabolism and eNOS expression, as well as the effect of sepiapterin (a precursor of BH4) and eNOS gene deletion, in a mice model of hypoxic pulmonary hypertension. In lungs, chronic hypoxia increased BH4 levels and eNOS expression, without modifying dihydrobiopterin (BH2, the oxidation product of BH4) levels, GTP cyclohydrolase-1 or dihydrofolate reductase expression (two key enzymes regulating BH4 availability). In intrapulmonary arteries, chronic hypoxia also increased expression of eNOS, but did not induce destabilisation of eNOS dimers into monomers. In hypoxic mice, sepiapterin prevented increase in right ventricular systolic pressure and right ventricular hypertrophy, whereas it modified neither remodelling nor alteration in vasomotor responses (hyper-responsiveness to phenylephrine, decrease in endothelium-dependent relaxation to acetylcholine) in intrapulmonary arteries. Finally, deletion of eNOS gene partially prevented hypoxia-induced increase in right ventricular systolic pressure, right ventricular hypertrophy and remodelling of intrapulmonary arteries. Collectively, these data demonstrate the absence of BH4/BH2 changes and eNOS dimer destabilisation, which may induce eNOS uncoupling during hypoxia-induced pulmonary hypertension. Thus, even though eNOS gene deletion and sepiapterin treatment exert protective effects on hypoxia-induced pulmonary vascular remodelling, increase on right ventricular pressure and / or right ventricular hypertrophy, these effects appear unrelated to biopterin-dependent eNOS uncoupling within pulmonary vasculature of hypoxic wild-type mice.
Subject(s)
Biopterins/metabolism , Hypertension, Pulmonary/metabolism , Hypoxia/complications , Nitric Oxide Synthase Type III/metabolism , Animals , Disease Models, Animal , Hypertension, Pulmonary/complications , Hypertension, Pulmonary/enzymology , Mice , Nitric Oxide Synthase Type III/genetics , Tetrahydrofolate Dehydrogenase/metabolismABSTRACT
OBJECTIVE: Estimate the effect of lifestyle adjustment activities in patients with metabolic syndrome treated by prescribed balneotherapy. METHODS: Observational pilot cohort study with 12-month follow-up after multidimensional lifestyle training (physical, dietary, educational) during 3-week standard stay in the spa town of Eugénie-les-Bains. RESULTS: Of 145 eligible patients, 97 were included; 63 were followed and analysable. At inclusion all had ≥3 National cholesterol education program-Adult treatment panel III (NCEP-ATPIII) criteria defining metabolic syndrome, 76.2% were female, mean age was 61.2 years. At the end of follow-up (median:10.4 months, Inter-Quartile Range: [6.7;11.4]), 48 of these 63 patients (76.2%) no longer had metabolic syndrome (95%CI [65.7;86.7]). These 48 patients without metabolic syndrome at the end of follow-up represented 49.5% of the 97 included (95%CI [39.5;59.4]). CONCLUSIONS: Future studies of lifestyle interventions taking advantage of the spa environment can be expected to find least one third of patients free of metabolic syndrome at the end of 12-month follow-up in the intervention group.
