In early stages of various pulmonary diseases, such as emphysema and fibrosis, the change in X-ray attenuation is not detectable with absorption-based radiography. To monitor the morphological ...changes that the alveoli network undergoes in the progression of these diseases, we propose using the dark-field signal, which is related to small-angle scattering in the sample. Combined with the absorption-based image, the dark-field signal enables better discrimination between healthy and emphysematous lung tissue in a mouse model. All measurements have been performed at 36 keV using a monochromatic laser-driven miniature synchrotron X-ray source (Compact Light Source). In this paper we present grating-based dark-field images of emphysematous vs. healthy lung tissue, where the strong dependence of the dark-field signal on mean alveolar size leads to improved diagnosis of emphysema in lung radiographs.
Chronic obstructive lung disease determines morbidity and mortality of patients with cystic fibrosis (CF). CF airways are characterized by a nonresolving neutrophilic inflammation. After pathogen ...contact or prolonged activation, neutrophils release DNA fibres decorated with antimicrobial proteins, forming neutrophil extracellular traps (NETs). NETs have been described to act in a beneficial way for innate host defense by bactericidal, fungicidal, and virucidal actions. On the other hand, excessive NET formation has been linked to the pathogenesis of autoinflammatory and autoimmune disease conditions. We quantified free DNA structures characteristic of NETs in airway fluids of CF patients and a mouse model with CF-like lung disease. Free DNA levels correlated with airflow obstruction, fungal colonization, and CXC chemokine levels in CF patients and CF-like mice. When viewed in combination, our results demonstrate that neutrophilic inflammation in CF airways is associated with abundant free DNA characteristic for NETosis, and suggest that free DNA may be implicated in lung function decline in patients with CF.
To assess whether grating-based X-ray dark-field imaging can increase the sensitivity of X-ray projection images in the diagnosis of pulmonary emphysema and allow for a more accurate assessment of ...emphysema distribution.
Lungs from three mice with pulmonary emphysema and three healthy mice were imaged ex vivo using a laser-driven compact synchrotron X-ray source. Median signal intensities of transmission (T), dark-field (V) and a combined parameter (normalized scatter) were compared between emphysema and control group. To determine the diagnostic value of each parameter in differentiating between healthy and emphysematous lung tissue, a receiver-operating-characteristic (ROC) curve analysis was performed both on a per-pixel and a per-individual basis. Parametric maps of emphysema distribution were generated using transmission, dark-field and normalized scatter signal and correlated with histopathology.
Transmission values relative to water were higher for emphysematous lungs than for control lungs (1.11 vs. 1.06, p<0.001). There was no difference in median dark-field signal intensities between both groups (0.66 vs. 0.66). Median normalized scatter was significantly lower in the emphysematous lungs compared to controls (4.9 vs. 10.8, p<0.001), and was the best parameter for differentiation of healthy vs. emphysematous lung tissue. In a per-pixel analysis, the area under the ROC curve (AUC) for the normalized scatter value was significantly higher than for transmission (0.86 vs. 0.78, p<0.001) and dark-field value (0.86 vs. 0.52, p<0.001) alone. Normalized scatter showed very high sensitivity for a wide range of specificity values (94% sensitivity at 75% specificity). Using the normalized scatter signal to display the regional distribution of emphysema provides color-coded parametric maps, which show the best correlation with histopathology.
In a murine model, the complementary information provided by X-ray transmission and dark-field images adds incremental diagnostic value in detecting pulmonary emphysema and visualizing its regional distribution as compared to conventional X-ray projections.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chronic obstructive pulmonary disease (COPD) is characterized by an irreversible loss of lung function and is one of the most prevalent and severe diseases worldwide. A major feature of COPD is ...emphysema, which is the progressive loss of alveolar tissue. Coactivator-associated arginine methyltransferase-1 (CARM1) regulates histone methylation and the transcription of genes involved in senescence, proliferation, and differentiation. Complete loss of CARM1 leads to disrupted differentiation and maturation of alveolar epithelial type II (ATII) cells. We thus hypothesized that CARM1 regulates the development and progression of emphysema. To address this, we investigated the contribution of CARM1 to alveolar rarefication using the mouse model of elastase-induced emphysema in vivo and small interfering (si)RNA-mediated knockdown in ATII-like LA4 cells in vitro. We demonstrate that emphysema progression in vivo is associated with a time-dependent down-regulation of CARM1. Importantly, elastase-treated CARM1 haploinsufficient mice show significantly increased airspace enlargement (52.5 ± 9.6 μm versus 38.8 ± 5.5 μm; P < 0.01) and lung compliance (2.8 ± 0.32 μl/cm H2O versus 2.4 ± 0.4 μl/cm H2O; P < 0.04) compared with controls. The knockdown of CARM1 in LA4 cells led to decreased sirtuin 1 expression (0.034 ± 0.003 versus 0.022 ± 0.001; P < 0.05) but increased expression of p16 (0.27 ± 0.013 versus 0.31 ± 0.010; P < 0.5) and p21 (0.81 ± 0.088 versus 1.28 ± 0.063; P < 0.01) and higher β-galactosidase-positive senescent cells (50.57 ± 7.36% versus 2.21 ± 0.34%; P < 0.001) compared with scrambled siRNA. We further demonstrated that CARM1 haploinsufficiency impairs transdifferentiation and wound healing (32.18 ± 0.9512% versus 8.769 ± 1.967%; P < 0.001) of alveolar epithelial cells. Overall, these results reveal a novel function of CARM1 in regulating emphysema development and premature lung aging via alveolar senescence as well as impaired regeneration, repair, and differentiation of ATII cells.
The nuclei of most vertebrate cells contain members of the high mobility group N (HMGN) protein family, which bind specifically to nucleosome core particles and affect chromatin structure and ...function, including transcription. Here, we study the biological role of this protein family by systematic analysis of phenotypes and tissue transcription profiles in mice lacking functional HMGN variants. Phenotypic analysis of Hmgn1tm1/tm1, Hmgn3tm1/tm1, and Hmgn5tm1/tm1 mice and their wild type littermates with a battery of standardized tests uncovered variant-specific abnormalities. Gene expression analysis of four different tissues in each of the Hmgntm1/tm1 lines reveals very little overlap between genes affected by specific variants in different tissues. Pathway analysis reveals that loss of an HMGN variant subtly affects expression of numerous genes in specific biological processes. We conclude that within the biological framework of an entire organism, HMGNs modulate the fidelity of the cellular transcriptional profile in a tissue- and HMGN variant-specific manner.
Background: The ubiquitously expressed high mobility group N (HMGN) protein variants affect chromatin structure and transcription.
Results: Hmgntm1/tm1 mice, which may express mutant proteins defective in nucleosome binding, display variant-specific phenotypes and tissue-specific altered transcription profiles.
Conclusion: HMGN variants fine tune the fidelity of the cellular transcription profile.
Significance: HMGN proteins impact the cellular phenotype by modulating the transcription levels of numerous genes.
The chitinase-like protein YKL-40 was found to be increased in patients with severe asthma and chronic obstructive pulmonary disease (COPD), two disease conditions featuring neutrophilic infiltrates. ...Based on these studies and a previous report indicating that neutrophils secrete YKL-40, we hypothesized that YKL-40 plays a key role in cystic fibrosis (CF) lung disease, a prototypic neutrophilic disease. The aim of this study was (i) to analyze YKL-40 levels in human and murine CF lung disease and (ii) to investigate whether YKL-40 single-nucleotide polymorphisms (SNPs) modulate CF lung disease severity. YKL-40 protein levels were quantified in serum and sputum supernatants from CF patients and control individuals. Levels of the murine homologue BRP-39 were analyzed in airway fluids from CF-like βENaC-Tg mice. YKL-40SNPs were analyzed in CF patients. YKL-40 levels were increased in sputum supernatants and in serum from CF patients compared to healthy control individuals. Within CF patients, YKL-40 levels were higher in sputum than in serum. BRP-39 levels were increased in airways fluids from βENaC-Tg mice compared to wild-type littermates. In both CF patients and βENaC-Tg mice, YKL-40/BRP-39 airway levels correlated with the severity of pulmonary obstruction. Two YKL-40 SNPs (rs871799 and rs880633) were found to modulate age-adjusted lung function in CF patients. YKL-40/BRP-39 levelsare increased in human and murine CF airway fluids, correlate with pulmonary function and modulate CF lung disease severity genetically. These findings suggest YKL-40 as a potential biomarker in CF lung disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Nuclear myosin I (NM1) is a nuclear isoform of the well-known "cytoplasmic" Myosin 1c protein (Myo1c). Located on the 11(th) chromosome in mice, NM1 results from an alternative start of transcription ...of the Myo1c gene adding an extra 16 amino acids at the N-terminus. Previous studies revealed its roles in RNA Polymerase I and RNA Polymerase II transcription, chromatin remodeling, and chromosomal movements. Its nuclear localization signal is localized in the middle of the molecule and therefore directs both Myosin 1c isoforms to the nucleus.
In order to trace specific functions of the NM1 isoform, we generated mice lacking the NM1 start codon without affecting the cytoplasmic Myo1c protein. Mutant mice were analyzed in a comprehensive phenotypic screen in cooperation with the German Mouse Clinic. Strikingly, no obvious phenotype related to previously described functions has been observed. However, we found minor changes in bone mineral density and the number and size of red blood cells in knock-out mice, which are most probably not related to previously described functions of NM1 in the nucleus. In Myo1c/NM1 depleted U2OS cells, the level of Pol I transcription was restored by overexpression of shRNA-resistant mouse Myo1c. Moreover, we found Myo1c interacting with Pol II. The ratio between Myo1c and NM1 proteins were similar in the nucleus and deletion of NM1 did not cause any compensatory overexpression of Myo1c protein.
We observed that Myo1c can replace NM1 in its nuclear functions. Amount of both proteins is nearly equal and NM1 knock-out does not cause any compensatory overexpression of Myo1c. We therefore suggest that both isoforms can substitute each other in nuclear processes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chronic obstructive pulmonary disease (COPD) is a devastating disease, for which no causal therapy is available.
To characterize WNT/β-catenin signaling in COPD in humans and elucidate its potential ...role as a preventive and therapeutic target in experimental emphysema in mice.
The expression, localization, and activity of WNT/β-catenin signaling was assessed in 12 COPD and 12 transplant donor samples using quantitative reverse transcriptase polymerase chain reaction, immunohistochemistry, and Western blotting. The role of WNT/β-catenin signaling was assessed in elastase- and cigarette smoke-induced emphysema and therapeutic modulation thereof in elastase-induced emphysema in TOPGAL reporter and wild-type mice in vivo.
No differences in the mRNA expression profile of the main WNT/β-catenin signaling components were observed comparing COPD and donor lung homogenates. Immunohistochemical analysis revealed reduced numbers of nuclear β-catenin-positive alveolar epithelial cells in COPD. Similarly, WNT/β-catenin signaling was down-regulated in both experimental emphysema models. Preventive and therapeutic, WNT/β-catenin activation by lithium chloride attenuated experimental emphysema, as assessed by decreased airspace enlargement, improved lung function, reduced collagen content, and elevated expression of alveolar epithelial cell markers.
Decreased WNT/β-catenin signaling is involved in parenchymal tissue destruction and impaired repair capacity in emphysema. These data indicate a crucial role of WNT/β-catenin signaling in lung repair mechanisms in vivo, and highlight WNT/β-catenin activation as a future therapeutic approach for emphysema.
To test the hypothesis that the joint distribution of x-ray transmission and dark-field signals obtained with a compact cone-beam preclinical scanner with a polychromatic source can be used to ...diagnose pulmonary emphysema in ex vivo murine lungs.
The animal care committee approved this study. Three excised murine lungs with pulmonary emphysema and three excised murine control lungs were imaged ex vivo by using a grating-based micro-computed tomographic (CT) scanner. To evaluate the diagnostic value, the natural logarithm of relative transmission and the natural logarithm of dark-field scatter signal were plotted on a per-pixel basis on a scatterplot. Probability density function was fit to the joint distribution by using principle component analysis. An emphysema map was calculated based on the fitted probability density function.
The two-dimensional scatterplot showed a characteristic difference between control and emphysematous lungs. Control lungs had lower average median logarithmic transmission (-0.29 vs -0.18, P = .1) and lower average dark-field signal (-0.54 vs -0.37, P = .1) than emphysematous lungs. The angle to the vertical axis of the fitted regions also varied significantly (7.8° for control lungs vs 15.9° for emphysematous lungs). The calculated emphysema distribution map showed good agreement with histologic findings.
X-ray dark-field scatter images of murine lungs obtained with a preclinical scanner can be used in the diagnosis of pulmonary emphysema.
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13122413/-/DC1.
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