17 research outputs found

    The telomerase activator TA-65 protects from cigarette smoke-induced small airway remodeling in mice through extra-telomeric effects

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    Abstract Small airway remodeling (SAR) is a key phenomenon of airflow obstruction in smokers, leading to chronic obstructive pulmonary disease (COPD). SAR results in an increased thickness of small airway walls, with a combination of peribronchiolar fibrosis with increased fibrous tissue and accumulation of mesenchymal and epithelial cells. SAR pathogenesis is still unclear but recent data suggest that alterations in telomerase activity could represent a possible underlying mechanism of SAR. Our study was dedicated to identify a potential protective role of TA-65, a pharmacological telomerase activator, in a cigarette smoke (CS) model of SAR in mice, and to further precise if extra-telomeric effects of telomerase, involving oxidative stress modulation, could explain it. C57BL/6J mice were daily exposed to air or CS during 4 weeks with or without a concomitant administration of TA-65 starting 7 days before CS exposure. Morphological analyses were performed, and mucus production, myofibroblast differentiation, collagen deposition, as well as transforming growth factor-β1 (TGF-β1) expression in the small airway walls were examined. In addition, the effects of TA-65 treatment on TGF-β expression, fibroblast-to-myofibroblast differentiation, reactive oxygen species (ROS) production and catalase expression and activity were evaluated in primary cultures of pulmonary fibroblasts and/or mouse embryonic fibroblasts in vitro. Exposure to CS during 4 weeks induced SAR in mice, characterized by small airway walls thickening and peribronchiolar fibrosis (increased deposition of collagen, expression of α-SMA in small airway walls), without mucus overproduction. Treatment of mice with TA-65 protected them from CS-induced SAR. This effect was associated with the prevention of CS-induced TGF-β expression in vivo, the blockade of TGF-β-induced myofibroblast differentiation, and the reduction of TGF-β-induced ROS production that correlates with an increase of catalase expression and activity. Our findings demonstrate that telomerase is a critical player of SAR, probably through extra-telomeric anti-oxidant effects, and therefore provide new insights in the understanding and treatment of COPD pathogenesis

    Potentiated Interaction between Ineffective Doses of Budesonide and Formoterol to Control the Inhaled Cadmium-Induced Up-Regulation of Metalloproteinases and Acute Pulmonary Inflammation in Rats

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    peer reviewedThe anti-inflammatory properties of glucocorticoids are well known but their protective effects exerted with a low potency against heavy metals-induced pulmonary inflammation remain unclear. In this study, a model of acute pulmonary inflammation induced by a single inhalation of cadmium in male Sprague-Dawley rats was used to investigate whether formoterol can improve the anti-inflammatory effects of budesonide. The cadmium-related inflammatory responses, including matrix metalloproteinase-9 (MMP-9) activity, were evaluated. Compared to the values obtained in rats exposed to cadmium, pretreatment of inhaled budesonide (0.5 mg/15 ml) elicited a significant decrease in total cell and neutrophil counts in bronchoalveolar lavage fluid (BALF) associated with a significant reduction of MMP-9 activity which was highly correlated with the number of inflammatory cells in BALF. Additionally, cadmium-induced lung injuries characterized by inflammatory cell infiltration within alveoli and the interstitium were attenuated by the pre-treatment of budesonide. Though the low concentration of budesonide (0.25 mg/15 ml) exerted a very limited inhibitory effects in the present rat model, its combination with an inefficient concentration of formoterol (0.5 mg/30 ml) showed an enhanced inhibitory effect on neutrophil and total cell counts as well as on the histological lung injuries associated with a potentiation of inhibition on the MMP-9 activity. In conclusion, high concentration of budesonide alone could partially protect the lungs against cadmium exposure induced-acute neutrophilic pulmonary inflammation via the inhibition of MMP-9 activity. The combination with formoterol could enhance the protective effects of both drugs, suggesting a new therapeutic strategy for the treatment of heavy metals-induced lung diseases

    Hemopressin and Other Bioactive Peptides from Cytosolic Proteins: Are These Non-Classical Neuropeptides?

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    Peptides perform many roles in cell–cell signaling; examples include neuropeptides, hormones, and growth factors. Although the vast majority of known neuropeptides are produced in the secretory pathway, a number of bioactive peptides are derived from cytosolic proteins. For example, the hemopressins are a family of peptides derived from alpha and beta hemoglobin which bind to the CB1 cannabinoid receptor, functioning as agonists or antagonists/inverse agonists depending on the size of the peptide. However, the finding that peptides derived from cytosolic proteins can affect receptors does not prove that these peptides are true endogenous signaling molecules. In order for the hemopressins and other peptides derived from cytosolic proteins to be considered neuropeptide-like signaling molecules, they must be synthesized in brain, they must be secreted in levels sufficient to produce effects, and either their synthesis or secretion should be regulated. If these criteria are met, we propose the name “non-classical neuropeptide” for this category of cytosolic bioactive peptide. This would be analogous to the non-classical neurotransmitters, such as nitric oxide and anandamide, which are not stored in secretory vesicles and released upon stimulation but are synthesized upon stimulation and constitutively released. We review some examples of cytosolic peptides from various protein precursors, describe potential mechanisms of their biosynthesis and secretion, and discuss the possibility that these peptides are signaling molecules in the brain, focusing on the criteria that these peptides would have to fill in order to be considered non-classical neuropeptides
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