[Show abstract][Hide abstract] ABSTRACT: TCR-dependent and costimulation signaling, cell division, and cytokine environment are major factors driving cytokines expression induced by CD4+ T cell activation. PEA-15 15 (Protein Enriched in Astrocyte / 15kDa) is an adaptor protein that regulates death receptor-induced apoptosis and proliferation signaling by binding to FADD and relocating ERK1/2 to the cytosol, respectively. By using PEA-15-deficient mice, we examined the role of PEA-15 in TCR-dependent cytokine production in CD4+ T cells. TCR-stimulated PEA-15-deficient CD4+ T cells exhibited defective progression through the cell cycle associated with impaired expression of cyclin E and phosphoRb, two ERK1/2-dependent proteins of the cell cycle. Accordingly, expression of the division cycle-dependent cytokines IL-2 and IFNγ, a Th1 cytokine, was reduced in stimulated PEA-15-deficient CD4+ T cells. This was associated with abnormal subcellular compartmentalization of activated ERK1/2 in PEA-15-deficient T cells. Furthermore, in vitro TCR-dependent differentiation of naive CD4+ CD62L+ PEA-15-deficient T cells was associated with a lower production of the Th2 cytokine, IL-4, whereas expression of the Th17-associated molecule IL4I1 was enhanced. Finally, a defective humoral response was shown in PEA-15-deficient mice in a model of red blood cell alloimmunization performed with Poly IC, a classical adjuvant of Th1 response in vivo. Collectively, our data suggest that PEA-15 contributes to the specification of the cytokine pattern of activated Th cells, thus highlighting a potential new target to interfere with T cell functional polarization and subsequent immune response.
[Show abstract][Hide abstract] ABSTRACT: The transcription factor p53 is overexpressed in the lung of patients with emphysema, but it remains unclear if it has a deleterious or protective effect in disease progression. We investigated the role of p53 in the elastase-induced emphysema model and the molecular underlining mechanisms.
Wild type (WT) and p53-/- mice were instilled with pancreatic porcine elastase 1UI. We quantified emphysema (morphometric analysis), CCL2 and TNFα in bronchoalveolar lavage (BAL) (ELISA), oxydative stress markers (heme oxygenase 1 (HO1), NAD(P)H dehydrogenase quinone 1 (NQO1) gene expression), MMP12 expression (immunofluorescence), and macrophages apoptosis (cleaved caspase-3 immunofluorescence).
p53 gene expression was upregulated in the lung of elastase-instilled mice. p53 deletion aggravated elastase-induced emphysema severity, pulmonary inflammation (macrophages and neutrophils number and CCL2 and TNFa levels in BAL) and lung oxidative stress. These findings were reproduced in WT mice transplanted with p53 -/- bone marrow cells, except the increase in CCL2. The increased number of macrophages in p53 -/- mice was not a consequence of reduced apoptosis or of an excess of chemotaxis toward CCL2. Macrophages expression of MMP12 was higher in p53 -/- mice compared to WT mice after elastase instillation.
These findings provide evidence that p53-/- mice and WT mice grafted with p53 -/- myeloid cells are more prone to develop elastase-induced emphysema, supporting a protective role of p53, and more precisely p53 expressed in macrophages, against emphysema development. The pivotal role played by macrophages in this phenomenon may involve the MMP12-TNFα pathway.
No preview · Article · Jun 2015 · American Journal of Respiratory Cell and Molecular Biology
[Show abstract][Hide abstract] ABSTRACT: Surface tunability and their ability to translocate plasma membranes make chemically functionalized carbon nanotubes (f-CNTs) promising intracellular delivery systems for therapeutic or diagnostic purposes in the central nervous system (CNS). The present study aimed to determine the biological impact of different types of multi-walled CNTs (MWNTs) on primary neuronal and glial cell populations isolated from foetal rat frontal cortex (FCO) and striatum (ST). Neurons from both brain regions were generally not affected by exposure to MWNTs as determined by a modified LDH assay. In contrast, the viability of mixed glia was reduced in ST-derived mixed glial cultures, but not in FCO-derived ones. Cytotoxicity was independent of MWNT type or dose, suggesting an inherent sensitivity to CNTs. Characterization of the cell populations in mixed glial cultures prior to nanotube exposure showed higher number of CD11b/c positive cells in the ST-derived mixed glial cultures. After exposure to MWNTs, CNT were uptaken more effectively by CD11b/c positive cells (microglia), compared to GFAP positive cells (astrocytes). When exposed to conditioned media from microglia enriched cultures exposed to MWNTs, ST-derived glial cultures secreted more NO than FCO-derived cells. These results suggested that the more significant cytotoxic response obtained from ST-derived mixed glia cultures was related to the higher number of microglial cells in this brain region. Our findings emphasize the role that resident macrophages of the CNS play in response to nanomaterials and the need to thoroughly investigate the brain region-specific effects towards designing implantable devices or delivery systems to the CNS.
[Show abstract][Hide abstract] ABSTRACT: Alteration of functional regenerative properties of parenchymal lung fibroblasts is widely proposed as a pathogenic mechanism for chronic obstructive pulmonary disease (COPD). However, what these functions are and how they are impaired in COPD remain poorly understood. Apart from the role of fibroblasts in producing extracellular matrix, recent studies in organs different from the lung suggest that such cells might contribute to repair processes by acting like mesenchymal stem cells. In addition, several reports sustain that the Hedgehog pathway is altered in COPD patients thus aggravating the disease. Nevertheless, whether this pathway is dysregulated in COPD fibroblasts remains unknown.
We investigated the stem cell features and the expression of Hedgehog components in human lung fibroblasts isolated from histologically-normal parenchymal tissue from 25 patients-8 non-smokers/non-COPD, 8 smokers-non COPD and 9 smokers with COPD-who were undergoing surgery for lung tumor resection.
We found that lung fibroblasts resemble mesenchymal stem cells in terms of cell surface marker expression, differentiation ability and immunosuppressive potential and that these properties were altered in lung fibroblasts from smokers and even more in COPD patients. Furthermore, we showed that some of these phenotypic changes can be explained by an over activation of the Hedgehog signaling in smoker and COPD fibroblasts.
Our study reveals that lung fibroblasts possess mesenchymal stem cell-features which are impaired in COPD via the contribution of an abnormal Hedgehog signaling. These processes should constitute a novel pathomechanism accounting for disease occurrence and progression.
[Show abstract][Hide abstract] ABSTRACT: Chronic obstructive pulmonary disease (COPD) is often associated with age-related systemic abnormalities that adversely affect the prognosis. Whether these manifestations are linked to the lung alterations or are independent complications of smoking remains unclear.
To look for aging-related systemic manifestations and telomere shortening in COPD patients and smokers with minor lung destruction responsible for a decline in the diffusing capacity for carbon monoxide (DLCO) corrected for alveolar volume (KCO).
Cross-sectional study in 301 individuals (100 with COPD, 100 smokers without COPD, and 101 nonsmokers without COPD).
Compared to control smokers, patients with COPD had higher aortic pulse-wave velocity (PWV), lower bone mineral density (BMD) and appendicular skeletal muscle mass index (ASMMI), and shorter telomere length (TL). Insulin resistance (HOMA-IR) and glomerular filtration rate (GFR) were similar between control smokers and COPD patients. Smokers did not differ from nonsmokers for any of these parameters. However, smokers with normal spirometry but low KCO had lower ASMMI values compared to those with normal KCO. Moreover, female smokers with low KCO, had lower BMD and shorter TL compared to those with normal KCO.
Aging-related abnormalities in patients with COPD are also found in smokers with minor lung dysfunction manifesting as a KCO decrease. Decreased KCO might be useful, particularly among women, for identifying smokers at high risk for aging-related systemic manifestations and telomere shortening.
[Show abstract][Hide abstract] ABSTRACT: -Cells exhibiting dysregulated growth may express telomerase reverse transcriptase (TERT), whose dual function consists in maintaining telomere length, in association with the RNA template molecule TERC and controlling cell growth. Here, we investigated lung TERT in human and experimental pulmonary hypertension (PH) and its role in controlling pulmonary artery-smooth muscle cell (PA-SMC) proliferation.
-Marked TERT expression and/or activity were found in lungs from patients with idiopathic PH and from mice with PH induced by hypoxia or serotonin-transporter overexpression (SM22-5HTT+ mice), chiefly within PA-SMCs. In cultured mouse PA-SMCs, TERT was expressed upon growth stimulation by serum. The TERT inhibitor imetelstat and the TERT activator TA65 abrogated and stimulated PA-SMC growth, respectively. PA-SMCs from PH mice showed a heightened proliferative phenotype associated with increased TERT expression, which was suppressed by imetelstat treatment. TERC(-/-) mice at generation 2 (G2) and TERT(-/-) mice at G2, G3, and G4 developed less severe PH than did wild-type mice exposed to chronic hypoxia, with less distal pulmonary-artery muscularization and fewer Ki67-stained proliferating PA-SMCs. Telomere length differed between TERC(-/-) and TERT(-/-) mice, whereas PH severity was similar in the two strains and across generations. Chronic imetelstat treatment reduced hypoxia-induced PH in wild-type mice or partially reversed established PH in SM22-5HTT+ mice, while simultaneously decreasing TERT expression. Opposite effects occurred in mice treated with TA65.
-Telomerase exerts telomere-independent effects on PA-SMC growth in PH and may constitute a treatment target for PH.
[Show abstract][Hide abstract] ABSTRACT: Les mécanismes biologiques du vieillissement et plus précisément de la sénescence cellulaire sont l’objet d’une recherche en plein développement. La sénescence cellulaire pourrait constituer un déterminant commun à de nombreuses maladies liées à l’âge et notamment à certaines pathologies pulmonaires chroniques telles la bronchopneumopathie chronique obstructive (BPCO) ou la fibrose pulmonaire idiopathique. De nombreux arguments suggèrent que ces maladies sont associées à une sénescence des cellules pulmonaires qui intervient dans la physiopathologie de l’atteinte respiratoire. De plus, ces pathologies sont associées à des manifestations systémiques, telles la déminéralisation osseuse, la fonte musculaire, l’athérosclérose, qui grèvent le pronostic et dont le mécanisme reste incompris. Dans cette revue, nous nous focaliserons sur la sénescence cellulaire et la BPCO. Deux hypothèses seront abordées : (1) le rôle de la sénescence cellulaire dans la physiopathologie des remaniements pulmonaires, parenchymateux et vasculaires ainsi que dans l’inflammation caractéristique de la maladie ; (2) le lien possible entre les altérations pulmonaires et les manifestations systémiques de la BPCO, qui pourraient traduire un processus général de vieillissement accéléré.
No preview · Article · Nov 2014 · Revue des Maladies Respiratoires
[Show abstract][Hide abstract] ABSTRACT: The rapid development of nanotechnologies is raising safety concerns because of the potential effects of engineered nanomaterials on human health, particularly at the respiratory level. Since the last decades, many in vivo studies have been interested in the pulmonary effects of different classes of nanomaterials. It has been shown that some of them can induce toxic effects, essentially depending on their physico-chemical characteristics, but other studies did not identify such effects. Inflammation and oxidative stress are currently the two main mechanisms described to explain the observed toxicity. However, the exact underlying mechanism(s) still remain(s) unknown and autophagy could represent an interesting candidate. Autophagy is a physiological process in which cytoplasmic components are digested via a lysosomal pathway. It has been shown that autophagy is involved in the pathogenesis and the progression of human diseases, and is able to modulate the oxidative stress and pro-inflammatory responses. A growing amount of literature suggests that a link between nanomaterial toxicity and autophagy impairment could exist. In this review, we will first summarize what is known about the respiratory effects of nanomaterials and we will then discuss the possible involvement of autophagy in this toxicity. This review should help understand why autophagy impairment could be taken as a promising candidate to fully understand nanomaterials toxicity.
[Show abstract][Hide abstract] ABSTRACT: Manufactured nanomaterials (MNMs) have the potential to improve everyday life as they can be utilised in numerous medical applications and day-to-day consumer products. However, this increased use has led to concerns about the potential environmental and human health impacts. The protein p53 is a key transcription factor implicated in cellular defence and reparative responses to various stress factors. Additionally, p53 has been implicated in cellular responses following exposure to some MNMs. Here, the role of the MNM mediated p53 induction and activation and its downstream effects following exposure to five well-characterised materials [namely two types of TiO2, two carbon black (CB), and one single-walled carbon nanotube (SWCNT)] were investigated. MNM internalisation, cellular viability, p53 protein induction and activation, oxidative stress, inflammation and apoptosis were measured in murine cell line and primary pulmonary macrophage models. It was observed that p53 was implicated in the biological responses to MNMs, with oxidative stress associated with p53 activation (only following exposure to the SWCNT). We demonstrate that p53 acted as an antioxidant and anti-inflammatory in macrophage responses to SWCNT and CB NMs. However, p53 was neither involved in MNM-induced cellular toxicity, nor in the apoptosis induced by these MNMs. Moreover, the physicochemical characteristics of MNMs seemed to influence their biological effects-SWCNT the materials with the largest surface area and a fibrous shape were the most cytotoxic in this study and were capable of the induction and activation of p53.
Full-text · Article · Aug 2014 · Archive für Toxikologie
[Show abstract][Hide abstract] ABSTRACT: Background:
Although major concerns exist regarding the potential consequences of human exposure to nanoparticles (NP), no human toxicological data is currently available. To address this issue, we took welders, who present various adverse respiratory outcomes, as a model population of occupational exposure to NP.The aim of this study was to evaluate if welding fume-issued NP could be responsible, at least partially, in the lung alterations observed in welders.
A combination of imaging and material science techniques including ((scanning) transmission electron microscopy ((S)TEM), energy dispersive X-ray (EDX), and X-ray microfluorescence (μXRF)), was used to characterize NP content in lung tissue from 21 welders and 21 matched control patients. Representative NP were synthesized, and their effects on macrophage inflammatory secretome and migration were evaluated, together with the effect of this macrophage inflammatory secretome on human lung primary fibroblasts differentiation.
Welding-related NP (Fe, Mn, Cr oxides essentially) were identified in lung tissue sections from welders, in macrophages present in the alveolar lumen and in fibrous regions. In vitro macrophage exposure to representative NP (Fe2O3, Fe3O4, MnFe2O4 and CrOOH) induced the production of a pro-inflammatory secretome (increased production of CXCL-8, IL-1ß, TNF-α, CCL-2, -3, -4, and to a lesser extent IL-6, CCL-7 and -22), and all but Fe3O4 NP induce an increased migration of macrophages (Boyden chamber). There was no effect of NP-exposed macrophage secretome on human primary lung fibroblasts differentiation.
Altogether, the data reported here strongly suggest that welding-related NP could be responsible, at least in part, for the pulmonary inflammation observed in welders. These results provide therefore the first evidence of a link between human exposure to NP and long-term pulmonary effects.
Full-text · Article · May 2014 · Particle and Fibre Toxicology