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.

• 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

Tick saliva contains a number of effector molecules that inhibit host immunity and facilitate pathogen transmission. How tick proteins regulate immune signaling, however, is incompletely understood. Here, we describe that loop 2 of sialostatin L2, an anti-inflammatory tick protein, binds to annexin A2 and impairs the formation of the NLRC4 inflammasome during infection with the rickettsial agent Anaplasma phagocytophilum Macrophages deficient in annexin A2 secreted significantly smaller amounts of interleukin-1β (IL-1β) and IL-18 and had a defect in NLRC4 inflammasome oligomerization and caspase-1 activation. Accordingly, Annexin a2-deficient mice were more susceptible to A. phagocytophilum infection and showed splenomegaly, thrombocytopenia, and monocytopenia. Providing translational support to our findings, better binding of annexin A2 to sialostatin L2 in sera from 21 out of 23 infected patients than in sera from control individuals was also demonstrated. Overall, we establish a unique mode of inflammasome evasion by a pathogen, centered on a blood-feeding arthropod.

• MeSH
• Anaplasma phagocytophilum genetika   imunologie   MeSH
• annexin A2 chemie   genetika   imunologie   MeSH
• arachnida jako vektory chemie   genetika   imunologie   MeSH
• cystatiny chemie   genetika   imunologie   MeSH
• ehrlichióza imunologie   mikrobiologie   patologie   MeSH
• Escherichia coli genetika   metabolismus   MeSH
• imunitní únik * MeSH
• inflamasomy genetika   imunologie   MeSH
• interleukin-18 genetika   imunologie   MeSH
• interleukin-1beta genetika   imunologie   MeSH
• kaspasa 1 genetika   imunologie   MeSH
• kaspasy genetika   imunologie   MeSH
• klíště chemie   genetika   imunologie   MeSH
• lidé MeSH
• makrofágy imunologie   mikrobiologie   MeSH
• molekulární modely MeSH
• myši MeSH
• protein - isoformy chemie   genetika   imunologie   MeSH
• proteiny regulující apoptózu chemie   genetika   imunologie   MeSH
• proteiny vázající vápník chemie   genetika   imunologie   MeSH
• regulace genové exprese MeSH
• rekombinantní proteiny chemie   genetika   imunologie   MeSH
• sekvence aminokyselin MeSH
• signální transdukce MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH