Pulmonary hypertension is a complex and heterogeneous condition with five main subtypes (groups). This review focuses on pulmonary hypertension caused by chronic hypoxia (hypoxic pulmonary hypertension, HPH, group 3). It is based mainly on our own experimental work, especially our collaboration with the group of Professor Herget, whose fifth anniversary of death we commemorate. We have found that oxidation and degradation of the extracellular matrix (ECM) in vitro, in either the presence or the absence of pro-inflammatory cells, activate vascular smooth muscle cell (VSMC) proliferation. Significant changes in the ECM of pulmonary arteries also occurred in vivo in hypoxic rats, namely a decrease in collagen VI and an increase in matrix metalloproteinase 9 (MMP-9) in the tunica media, which may also contribute to the growth activation of VSMCs. The proliferation of VSMCs was also enhanced in their co-culture with macrophages, most likely due to the paracrine production of growth factors in these cells. However, hypoxia itself has a dual effect: on the one hand, it can activate VSMC proliferation and hyperplasia, but on the other hand, it can also induce VSMC hypertrophy and increased expression of contractile markers in these cells. The influence of hypoxia-inducible factors, microRNAs and galectin-3 in the initiation and development of HPH, and the role of cell types other than VSMCs (endothelial cells, adventitial fibroblasts) are also discussed. Keywords: Vasoconstriction, Remodeling, Oxidation, Degradation, Extracellular matrix, Collagen, Proteolytic enzymes, Metalloproteinases, Macrophages, Mast cells, Smooth muscle cells, Endothelial cells, Fibroblasts, Mesenchymal stem cells, Hypoxia-inducible factor, microRNA, Galectins, Hyperplasia, Hypertrophy, Therapy of hypoxic pulmonary hypertension.

• MeSH
• hypoxie * metabolismus   MeSH
• lidé MeSH
• myocyty hladké svaloviny * metabolismus   patologie   MeSH
• plicní hypertenze * metabolismus   patologie   MeSH
• proliferace buněk MeSH
• svaly hladké cévní * metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Pulmonary hypertension (PH) is a heterogeneous and life-threatening cardiopulmonary disorder in which mitochondrial dysfunction is believed to drive pathogenesis, although the underlying mechanisms remain unclear. To determine if abnormal SIRT3 (sirtuin 3) activity is related to mitochondrial dysfunction in adventitial fibroblasts from patients with idiopathic pulmonary arterial hypertension (IPAH) and hypoxic PH calves (PH-Fibs) and whether SIRT3 could be a potential therapeutic target to improve mitochondrial function, SIRT3 concentrations in control fibroblasts, PH-Fibs, and lung tissues were determined using quantitative real-time PCR and western blot. SIRT3 deacetylase activity in cells and lung tissues was determined using western blot, immunohistochemistry staining, and immunoprecipitation. Glycolysis and mitochondrial function in fibroblasts were measured using respiratory analysis and fluorescence-lifetime imaging microscopy. The effects of restoring SIRT3 activity (by overexpression of SIRT3 with plasmid, activation SIRT3 with honokiol, and supplementation with the SIRT3 cofactor nicotinamide adenine dinucleotide [NAD+]) on mitochondrial protein acetylation, mitochondrial function, cell proliferation, and gene expression in PH-Fibs were also investigated. We found that SIRT3 concentrations were decreased in PH-Fibs and PH lung tissues, and its cofactor, NAD+, was also decreased in PH-Fibs. Increased acetylation in overall mitochondrial proteins and SIRT3-specific targets (MPC1 [mitochondrial pyruvate carrier 1] and MnSOD2 [mitochondrial superoxide dismutase]), as well as decreased MnSOD2 activity, was identified in PH-Fibs and PH lung tissues. Normalization of SIRT3 activity, by increasing its expression with plasmid or with honokiol and supplementation with its cofactor NAD+, reduced mitochondrial protein acetylation, improved mitochondrial function, inhibited proliferation, and induced apoptosis in PH-Fibs. Thus, our study demonstrated that restoration of SIRT3 activity in PH-Fibs can reduce mitochondrial protein acetylation and restore mitochondrial function and PH-Fib phenotype in PH.

• Klíčová slova
• SIRT3, honokiol, mitochondria, nicotinamide adenine dinucleotide, pulmonary hypertension,
• MeSH
• fibroblasty metabolismus   MeSH
• lidé MeSH
• mitochondriální proteiny metabolismus   MeSH
• mitochondrie metabolismus   MeSH
• NAD metabolismus   MeSH
• plicní hypertenze * patologie   MeSH
• sirtuin 3 * genetika   metabolismus   MeSH
• skot MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• honokiol MeSH Prohlížeč
• mitochondriální proteiny MeSH
• NAD MeSH
• SIRT3 protein, human MeSH Prohlížeč
• sirtuin 3 * MeSH

Progress in mass spectroscopy of posttranslational oxidative modifications has enabled researchers to experimentally verify the concept of redox signaling. We focus here on redox signaling originating from mitochondria under physiological situations, discussing mechanisms of transient redox burst in mitochondria, as well as the possible ways to transfer such redox signals to specific extramitochondrial targets. A role of peroxiredoxins is described which enables redox relay to other targets. Examples of mitochondrial redox signaling are discussed: initiation of hypoxia-inducible factor (HIF) responses; retrograde redox signaling to PGC1α during exercise in skeletal muscle; redox signaling in innate immune cells; redox stimulation of insulin secretion, and other physiological situations.

• Klíčová slova
• H2O2 diffusion, HIF, Redox signaling from mitochondria, mitochondrial superoxide formation, peroxiredoxins, redox-regulation of kinases,
• MeSH
• beta-buňky metabolismus   MeSH
• hypoxie metabolismus   MeSH
• imunita fyziologie   MeSH
• kosterní svaly metabolismus   MeSH
• mitochondrie metabolismus   MeSH
• oxidace-redukce MeSH
• peroxid vodíku metabolismus   MeSH
• peroxiredoxiny MeSH
• posttranslační úpravy proteinů MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• signální transdukce fyziologie   MeSH
• superoxidy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• peroxid vodíku MeSH
• peroxiredoxiny MeSH
• reaktivní formy kyslíku MeSH
• superoxidy MeSH

BACKGROUND: An emerging metabolic theory of pulmonary hypertension (PH) suggests that cellular and mitochondrial metabolic dysfunction underlies the pathology of this disease. We and others have previously demonstrated the existence of hyperproliferative, apoptosis-resistant, proinflammatory adventitial fibroblasts from human and bovine hypertensive pulmonary arterial walls (PH-Fibs) that exhibit constitutive reprogramming of glycolytic and mitochondrial metabolism, accompanied by an increased ratio of glucose catabolism through glycolysis versus the tricarboxylic acid cycle. However, the mechanisms responsible for these metabolic alterations in PH-Fibs remain unknown. We hypothesized that in PH-Fibs microRNA-124 (miR-124) regulates PTBP1 (polypyrimidine tract binding protein 1) expression to control alternative splicing of pyruvate kinase muscle (PKM) isoforms 1 and 2, resulting in an increased PKM2/PKM1 ratio, which promotes glycolysis and proliferation even in aerobic environments. METHODS: Pulmonary adventitial fibroblasts were isolated from calves and humans with severe PH (PH-Fibs) and from normal subjects. PTBP1 gene knockdown was achieved via PTBP1-siRNA; restoration of miR-124 was performed with miR-124 mimic. TEPP-46 and shikonin were used to manipulate PKM2 glycolytic function. Histone deacetylase inhibitors were used to treat cells. Metabolic products were determined by mass spectrometry-based metabolomics analyses, and mitochondrial function was analyzed by confocal microscopy and spectrofluorometry. RESULTS: We detected an increased PKM2/PKM1 ratio in PH-Fibs compared with normal subjects. PKM2 inhibition reversed the glycolytic status of PH-Fibs, decreased their cell proliferation, and attenuated macrophage interleukin-1β expression. Furthermore, normalizing the PKM2/PKM1 ratio in PH-Fibs by miR-124 overexpression or PTBP1 knockdown reversed the glycolytic phenotype (decreased the production of glycolytic intermediates and byproducts, ie, lactate), rescued mitochondrial reprogramming, and decreased cell proliferation. Pharmacological manipulation of PKM2 activity with TEPP-46 and shikonin or treatment with histone deacetylase inhibitors produced similar results. CONCLUSIONS: In PH, miR-124, through the alternative splicing factor PTBP1, regulates the PKM2/PKM1 ratio, the overall metabolic, proliferative, and inflammatory state of cells. This PH phenotype can be rescued with interventions at various levels of the metabolic cascade. These findings suggest a more integrated view of vascular cell metabolism, which may open unique therapeutic prospects in targeting the dynamic glycolytic and mitochondrial interactions and between mesenchymal inflammatory cells in PH.

• Klíčová slova
• TEEP-46, hypoxia, metabolism, mitochondria, pyruvate kinase, shikonin, splicing factors,
• MeSH
• alternativní sestřih MeSH
• antagomiry metabolismus   MeSH
• cévní endotel cytologie   MeSH
• fibroblasty cytologie   účinky léků   metabolismus   MeSH
• glykolýza MeSH
• heterogenní jaderné ribonukleoproteiny antagonisté a inhibitory   genetika   metabolismus   MeSH
• inhibitory histondeacetylas farmakologie   MeSH
• interleukin-1beta metabolismus   MeSH
• lidé MeSH
• makrofágy cytologie   imunologie   metabolismus   MeSH
• mikro RNA antagonisté a inhibitory   genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• naftochinony farmakologie   MeSH
• plicní hypertenze metabolismus   patologie   MeSH
• proliferace buněk MeSH
• protein - isoformy antagonisté a inhibitory   genetika   metabolismus   MeSH
• protein vázající polypyrimidinové úseky RNA antagonisté a inhibitory   genetika   metabolismus   MeSH
• pyruvátkinasa antagonisté a inhibitory   genetika   metabolismus   MeSH
• RNA interference MeSH
• skot MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antagomiry MeSH
• heterogenní jaderné ribonukleoproteiny MeSH
• inhibitory histondeacetylas MeSH
• interleukin-1beta MeSH
• mikro RNA MeSH
• MIRN124 microRNA, human MeSH Prohlížeč
• naftochinony MeSH
• protein - isoformy MeSH
• protein vázající polypyrimidinové úseky RNA MeSH
• PTBP1 protein, human MeSH Prohlížeč
• pyruvátkinasa MeSH
• shikonin MeSH Prohlížeč