The Hyperproliferative, Apoptosis-Resistant Phenotype of Pulmonary Microvascular Endothelial Cells in Idiopathic Pulmonary Arterial Hypertension is Partially Mediated by Autocrine Production of FGF-2

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Dichloroacetate treatment partially regresses established pulmonary hypertension in mice with SM22alpha-targeted overexpression of the serotonin transporter.

Voltage-gated potassium (Kv)1.5 is decreased in pulmonary arteries (PAs) of patients with idiopathic pulmonary arterial hypertension (IPAH) and in experimental models including mice with SM22alpha-targeted overexpression of the serotonin transporter (5-HTT). The mechanisms underlying these abnormalities, however, remain unknown. Dichloroacetate (DCA) inhibits chronic hypoxia- or monocrotaline-induced PAH by inhibiting nuclear factor of activated T-cells (NFAT)c2 and increasing Kv1.5. Therefore, we hypothesized that DCA could regress established PAH in SM22-5-HTT+ mice. We evaluated pulmonary hemodynamics, vascular remodeling, NFATc2, and Kv1.5 protein in 20-wk-old SM22-5-HTT+ or wild-type mice treated for 1, 7, and 21 d with DCA, cyclosporine-A (NFAT inhibitor), or vehicle. DCA partially reversed PAH in SM22-5-HTT+ mice by decreasing proliferation and increasing apoptosis in muscularized PAs. Furthermore, serotonin (10(-8)-10(-6) M) dose-dependently increased PA-smooth muscle cell (PA-SMC) proliferation in culture (EC(50)=0.97 x 10(-7) M) and DCA (5 x 10(-4) M) vs. PBS markedly reduced the growth of PA-SMC from IPAH and control patients treated with the highest dose of serotonin by 50 and 30%, respectively. Finally, although serotonin induces NFATc2 activation in PA-SMCs, inhibition of NFATc2 alone with cyclosporine-A was not sufficient for reversing PAH in this model. Our results support the possibility that DCA may be an interesting agent for investigation in patients with PAH.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Dichloroacetate Treatment Partially Regresses Established Pulmonary Hypertension in Mice with SM22α-Targeted Over-express

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Serotonin transporter inhibition prevents and reverses monocrotaline-induced pulmonary hypertension in rats.: 5-HT Transporter Inhibition Prevents PH

9 pagesInternational audienceBACKGROUND: Progression of pulmonary hypertension (PH) is associated with increased lung expression of the serotonin transporter (5-HTT), which leads to hyperplasia of the pulmonary artery smooth muscle cells (PA-SMCs). Given the postulated causal relation between 5-HTT overexpression and PH, we herein investigated whether the highly selective 5-HTT inhibitor fluoxetine prevented and/or reversed PH induced by monocrotaline (MCT) in rats. Selective 5-HT(1B/1D), 5-HT(2A), and 5-HT(2B) receptor antagonists were used for comparative testing. METHODS AND RESULTS: MCT injection (60 mg/kg SC) was followed by an early peak in lung 5-HTT expression on day 1, which preceded the onset of PH. Established PH on day 15 was associated with a sustained 5-HTT increase. Continued fluoxetine treatment completely prevented PA-SMC proliferation and PH development and also suppressed the late 5-HTT increase, without affecting the early peak. The 5-HT receptor antagonists did not affect PH. Fluoxetine (10 mg . kg(-1) . d(-1) PO) started 3 weeks after MCT injection completely reversed established PH, normalizing PA pressure and structure. MCT-induced PH was also associated with increased expression of various cytokines, but only interleukin-1beta and monocyte chemotactic protein-1 increased at the early phase and stimulated 5-HTT expression by cultured PA-SMCs. CONCLUSIONS: Upregulation of lung 5-HTT induced by MCT appears necessary to initiate the development of pulmonary vascular remodeling, whereas a sustained increase in 5-HTT expression may underlie both the progression and the maintenance of MCT-induced PH. Complete reversal of established PH by fluoxetine provides a rationale for new therapeutic strategies in human PH

Dysregulated bone morphogenetic protéin signaling in pulmonary arterial hypertension

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Dichloroacetate Treatment Partially Regresses Established Pulmonary Hypertension In Mice With SM22±-Targeted Over-expression Of The Serotonin Transporter

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Human CCR6+Th17 lymphocytes are highly sensitive to radiation-induced senescence and are a potential target for prevention of radiation-induced toxicity

PURPOSE: To study the sensitivity of different peripheral CD4+ T-lymphocyte subsets to IR and identify potential targets for the prevention and/or treatment of radiation-induced toxicity. METHODS AND MATERIALS: This study was performed on peripheral blood mononuclear cells (PBMCs) or sorted peripheral memory lymphocytes of CCR6+ mucosa-homing Th17/CCR6negTh and regulatory T (Treg) subtypes of healthy volunteers. Cells were irradiated with a 2Gy +/- pharmacological inhibitors of different signaling pathways. Senescence of irradiated cells was assessed by resistance to apoptosis and determination of various senescence-associated biomarkers (senescence associated β-galactosidase (SA-β-Gal) activity, p16Ink4a-, p21Cdkn1a-, γH2A.X-, H2A.J expression). Cytokine production was measured in supernatants of irradiated cells by Luminex technology. RESULTS: Not all CD4+ memory T lymphocyte subsets were equally radiosensitive. High sensitivity of CCR6+Th17 lymphocytes to IR-induced senescence was shown by expression of the histone variant H2A.J, higher SA-β-Gal activity and upregulation of p16Ink4a and p21Cdkn1a expression. Lower Annexin V staining and cleaved caspase-3, and higher expression of anti-apoptotic genes Bcl-2 and Bcl-xL LF showed that CCR6+Th17 lymphocytes were more resistant to IR-induced apoptosis than CCR6neg memory Th and Treg lymphocytes. After a 2 Gy IR, both CCR6+Th17 and CCR6neg cells acquired a moderate senescence-associated secretory phenotype (SASP) but only CCR6+Th17 cells secreted IL-8 and VEGF-A. Pharmacological targeting of ROS, MAPKs, and mTOR signaling pathways prevented the expression of senescent markers and IL-8 and VEGF-A expression by CCR6+Th17 cells after IR. CONCLUSION: This study suggests that IR induces senescence of CCR6+Th17 lymphocytes associated with secretion of IL-8 and VEGF-A that may be detrimental to the irradiated tissue. ROS-MAPKs signaling pathways are candidate targets to prevent this CCR6+Th17-dependent radiation-induced potential toxicity. Finally, the ratio of circulating H2A.J+ senescent CCR6+Th17/CD4+ T lymphocytes may be a candidate marker of individual intrinsic radiosensitivity

Proteomic Analysis of Nasal Epithelial Cells from Cystic Fibrosis Patients

International audienceThe pathophysiology of cystic fibrosis (CF) lung disease remains incompletely understood. New explanations for the pathogenesis of CF lung disease may be discovered by studying the patterns of protein expression in cultured human nasal epithelial cells (HNEC). To that aim, we compared the level of protein expressions in primary cultures of HNEC from nasal polyps secondary to CF (CFNP, n = 4), primary nasal polyps (NP, n = 8) and control mucosa (CTRL, n = 4) using isobaric tag for relative and absolute quantification (iTRAQ) labeling coupled with liquid chromatography (LC)-MS-MS. The analysis of the data revealed 42 deregulated protein expressions in CFNP compared to NP and CTRL, suggesting that these alterations are related to CF. Overall, AmiGo analysis highlighted six major pathways important for cell functions that seem to be impaired: metabolism, G protein process, inflammation and oxidative stress response, protein folding, proteolysis and structural proteins. Among them, glucose and fatty acid metabolic pathways could be impaired in CF with nine deregulated proteins. Our proteomic study provides a reproducible set of differentially expressed proteins in airway epithelial cells from CF patients and reveals many novel deregulated proteins that could lead to further studies aiming to clarify the involvement of such proteins in CF pathophysiology