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BACKGROUND: Dysregulation of Fractalkine (CX3CL1) and its receptor CX3CR1 has been linked to the pathobiology of chronic inflammatory conditions. We explored CX3CL1 in systemic sclerosis (SSc) related progressive interstitial lung disease (ILD) and pulmonary hypertension (PH) in two different but complementary sources of biomaterial. METHODS: We collected lung tissue at the time of lung transplantation at UCLA from SSc-ILD patients (n = 12) and healthy donors (n = 12); and serum samples from the prospective Oslo University Hospital SSc cohort (n = 292) and healthy donors (n = 100). CX3CL1 was measured by ELISA. Cellular sources of CX3CL1/CX3CR1 in lung tissues were determined by immunohistochemistry and immunofluorescence. ILD progression and new onset PH endpoints were analysed. RESULTS: CX3CL1 concentrations were increased in SSc in lung tissue as well as in sera. In the UCLA cohort, CX3CL1 was highly correlated with DLCO. In the SSc-ILD lungs, CX3CL1 was identified in reactive type II pneumocytes and airway epithelial cells. CX3CR1 stained infiltrating interstitial mononuclear cells, especially plasma cells. In the Oslo cohort, CX3CL1 correlated with anti-Topoisomerase-I-antibody and lung fibrosis. CX3CL1 was associated with ILD progression in multivariable regression analysis but not PH. CONCLUSION: CX3CL1 is associated with progressive SSc-ILD but not SSc-PH. The CX3CR1/CX3CL1-biological axis may be involved in recruiting antibody secreting plasma cells to SSc lungs, thereby contributing to the immune-mediated pathobiology of SSc-ILD.

BackgroundChronic Lung Allograft Dysfunction (CLAD) is the main limitation to long-term survival after lung transplantation. Although CLAD is usually not responsive to treatment, earlier identification may improve treatment prospects.MethodsIn a nested case control study, 1-year post transplant surveillance bronchoalveolar lavage (BAL) fluid samples were obtained from incipient CLAD (n = 9) and CLAD free (n = 8) lung transplant recipients. Incipient CLAD cases were diagnosed with CLAD within 2 years, while controls were free from CLAD for at least 4 years following bronchoscopy. Transcription profiles in the BAL cell pellets were assayed with the HG-U133 Plus 2.0 microarray (Affymetrix). Differential gene expression analysis, based on an absolute fold change (incipient CLAD vs no CLAD) >2.0 and an unadjusted p-value ≤0.05, generated a candidate list containing 55 differentially expressed probe sets (51 up-regulated, 4 down-regulated).ResultsThe cell pellets in incipient CLAD cases were skewed toward immune response pathways, dominated by genes related to recruitment, retention, activation and proliferation of cytotoxic lymphocytes (CD8+ T-cells and natural killer cells). Both hierarchical clustering and a supervised machine learning tool were able to correctly categorize most samples (82.3% and 94.1% respectively) into incipient CLAD and CLAD-free categories.ConclusionsThese findings suggest that a pathobiology, similar to AR, precedes a clinical diagnosis of CLAD. A larger prospective investigation of the BAL cell pellet transcriptome as a biomarker for CLAD risk stratification is warranted.

RationaleSince the pathogenesis of chronic lung allograft dysfunction (CLAD) remains poorly defined with no known effective therapies, the identification and study of key events which increase CLAD risk is a critical step towards improving outcomes. We hypothesized that bronchoalveolar lavage fluid (BALF) CXCR3 ligand concentrations would be augmented during organizing pneumonia (OP) and that episodes of OP with marked chemokine elevations would be associated with significantly higher CLAD risk.MethodsAll transbronchial biopsies (TBBX) from patients who received lung transplantation between 2000 to 2010 were reviewed. BALF concentrations of the CXCR3 ligands (CXCL9, CXCL10 and CXCL11) were compared between episodes of OP and "healthy" biopsies using linear mixed-effects models. The association between CXCR3 ligand concentrations during OP and CLAD risk was evaluated using proportional hazards models with time-dependent covariates.ResultsThere were 1894 bronchoscopies with TBBX evaluated from 441 lung transplant recipients with 169 (9%) episodes of OP and 907 (49%) non-OP histopathologic injuries. 62 (37%) episodes of OP were observed during routine surveillance bronchoscopy. Eight hundred thirty-eight (44%) TBBXs had no histopathology and were classified as "healthy" biopsies. There were marked elevations in BALF CXCR3 ligand concentrations during OP compared with "healthy" biopsies. In multivariable models adjusted for other injury patterns, OP did not significantly increase the risk of CLAD when BAL CXCR3 chemokine concentrations were not taken into account. However, OP with elevated CXCR3 ligands markedly increased CLAD risk in a dose-response manner. An episode of OP with CXCR3 concentrations greater than the 25th, 50th and 75th percentiles had HRs for CLAD of 1.5 (95% CI 1.0-2.3), 1.9 (95% CI 1.2-2.8) and 2.2 (95% CI 1.4-3.4), respectively.ConclusionsThis study identifies OP, a relatively uncommon histopathologic finding after lung transplantation, as a major risk factor for CLAD development when considered in the context of increased allograft expression of interferon-γ inducible ELR- CXC chemokines. We further demonstrate for the first time, the prognostic importance of BALF CXCR3 ligand concentrations during OP on subsequent CLAD risk.

BACKGROUND:Dysregulation of Fractalkine (CX3CL1) and its receptor CX3CR1 has been linked to the pathobiology of chronic inflammatory conditions. We explored CX3CL1 in systemic sclerosis (SSc) related progressive interstitial lung disease (ILD) and pulmonary hypertension (PH) in two different but complementary sources of biomaterial. METHODS:We collected lung tissue at the time of lung transplantation at UCLA from SSc-ILD patients (n = 12) and healthy donors (n = 12); and serum samples from the prospective Oslo University Hospital SSc cohort (n = 292) and healthy donors (n = 100). CX3CL1 was measured by ELISA. Cellular sources of CX3CL1/CX3CR1 in lung tissues were determined by immunohistochemistry and immunofluorescence. ILD progression and new onset PH endpoints were analysed. RESULTS:CX3CL1 concentrations were increased in SSc in lung tissue as well as in sera. In the UCLA cohort, CX3CL1 was highly correlated with DLCO. In the SSc-ILD lungs, CX3CL1 was identified in reactive type II pneumocytes and airway epithelial cells. CX3CR1 stained infiltrating interstitial mononuclear cells, especially plasma cells. In the Oslo cohort, CX3CL1 correlated with anti-Topoisomerase-I-antibody and lung fibrosis. CX3CL1 was associated with ILD progression in multivariable regression analysis but not PH. CONCLUSION:CX3CL1 is associated with progressive SSc-ILD but not SSc-PH. The CX3CR1/CX3CL1-biological axis may be involved in recruiting antibody secreting plasma cells to SSc lungs, thereby contributing to the immune-mediated pathobiology of SSc-ILD.

BACKGROUND:Chronic Lung Allograft Dysfunction (CLAD) is the main limitation to long-term survival after lung transplantation. Although CLAD is usually not responsive to treatment, earlier identification may improve treatment prospects. METHODS:In a nested case control study, 1-year post transplant surveillance bronchoalveolar lavage (BAL) fluid samples were obtained from incipient CLAD (n = 9) and CLAD free (n = 8) lung transplant recipients. Incipient CLAD cases were diagnosed with CLAD within 2 years, while controls were free from CLAD for at least 4 years following bronchoscopy. Transcription profiles in the BAL cell pellets were assayed with the HG-U133 Plus 2.0 microarray (Affymetrix). Differential gene expression analysis, based on an absolute fold change (incipient CLAD vs no CLAD) >2.0 and an unadjusted p-value ≤0.05, generated a candidate list containing 55 differentially expressed probe sets (51 up-regulated, 4 down-regulated). RESULTS:The cell pellets in incipient CLAD cases were skewed toward immune response pathways, dominated by genes related to recruitment, retention, activation and proliferation of cytotoxic lymphocytes (CD8+ T-cells and natural killer cells). Both hierarchical clustering and a supervised machine learning tool were able to correctly categorize most samples (82.3% and 94.1% respectively) into incipient CLAD and CLAD-free categories. CONCLUSIONS:These findings suggest that a pathobiology, similar to AR, precedes a clinical diagnosis of CLAD. A larger prospective investigation of the BAL cell pellet transcriptome as a biomarker for CLAD risk stratification is warranted.

Since the pathogenesis of chronic lung allograft dysfunction (CLAD) remains poorly defined with no known effective therapies, the identification and study of key events which increase CLAD risk is a critical step towards improving outcomes. We hypothesized that bronchoalveolar lavage fluid (BALF) CXCR3 ligand concentrations would be augmented during organizing pneumonia (OP) and that episodes of OP with marked chemokine elevations would be associated with significantly higher CLAD risk.All transbronchial biopsies (TBBX) from patients who received lung transplantation between 2000 to 2010 were reviewed. BALF concentrations of the CXCR3 ligands (CXCL9, CXCL10 and CXCL11) were compared between episodes of OP and "healthy" biopsies using linear mixed-effects models. The association between CXCR3 ligand concentrations during OP and CLAD risk was evaluated using proportional hazards models with time-dependent covariates.There were 1894 bronchoscopies with TBBX evaluated from 441 lung transplant recipients with 169 (9%) episodes of OP and 907 (49%) non-OP histopathologic injuries. 62 (37%) episodes of OP were observed during routine surveillance bronchoscopy. Eight hundred thirty-eight (44%) TBBXs had no histopathology and were classified as "healthy" biopsies. There were marked elevations in BALF CXCR3 ligand concentrations during OP compared with "healthy" biopsies. In multivariable models adjusted for other injury patterns, OP did not significantly increase the risk of CLAD when BAL CXCR3 chemokine concentrations were not taken into account. However, OP with elevated CXCR3 ligands markedly increased CLAD risk in a dose-response manner. An episode of OP with CXCR3 concentrations greater than the 25th, 50th and 75th percentiles had HRs for CLAD of 1.5 (95% CI 1.0-2.3), 1.9 (95% CI 1.2-2.8) and 2.2 (95% CI 1.4-3.4), respectively.This study identifies OP, a relatively uncommon histopathologic finding after lung transplantation, as a major risk factor for CLAD development when considered in the context of increased allograft expression of interferon-γ inducible ELR- CXC chemokines. We further demonstrate for the first time, the prognostic importance of BALF CXCR3 ligand concentrations during OP on subsequent CLAD risk.

Mediator, an evolutionarily conserved multi-protein complex consisting of about 30 subunits, is a key component of the polymerase II mediated gene transcription. Germline deletion of the Mediator subunit 1 (Med1) of the Mediator in mice results in mid-gestational embryonic lethality with developmental impairment of multiple organs including heart. Here we show that cardiomyocyte-specific deletion of Med1 in mice (csMed1-/-) during late gestational and early postnatal development by intercrossing Med1fl/fl mice to α-MyHC-Cre transgenic mice results in lethality within 10 days after weaning due to dilated cardiomyopathy-related ventricular dilation and heart failure. The csMed1-/- mouse heart manifests mitochondrial damage, increased apoptosis and interstitial fibrosis. Global gene expression analysis revealed that loss of Med1 in heart down-regulates more than 200 genes including Acadm, Cacna1s, Atp2a2, Ryr2, Pde1c, Pln, PGC1α, and PGC1β that are critical for calcium signaling, cardiac muscle contraction, arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy and peroxisome proliferator-activated receptor regulated energy metabolism. Many genes essential for oxidative phosphorylation and proper mitochondrial function such as genes coding for the succinate dehydrogenase subunits of the mitochondrial complex II are also down-regulated in csMed1-/- heart contributing to myocardial injury. Data also showed up-regulation of about 180 genes including Tgfb2, Ace, Atf3, Ctgf, Angpt14, Col9a2, Wisp2, Nppa, Nppb, and Actn1 that are linked to cardiac muscle contraction, cardiac hypertrophy, cardiac fibrosis and myocardial injury. Furthermore, we demonstrate that cardiac specific deletion of Med1 in adult mice using tamoxifen-inducible Cre approach (TmcsMed1-/-), results in rapid development of cardiomyopathy and death within 4 weeks. We found that the key findings of the csMed1-/- studies described above are highly reproducible in TmcsMed1-/- mouse heart. Collectively, these observations suggest that Med1 plays a critical role in the maintenance of heart function impacting on multiple metabolic, compensatory and reparative pathways with a likely therapeutic potential in the management of heart failure.

[This corrects the article DOI: 10.1371/journal.pone.0160755.].

BackgroundTumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factor-inducible 14 (Fn14) are upregulated after myocardial infarction (MI) in both humans and mice. They modulate inflammation and the extracellular matrix, and could therefore be important for healing and remodeling after MI. However, the function of TWEAK after MI remains poorly defined.Methods and resultsFollowing ligation of the left coronary artery, mice were injected twice per week with a recombinant human serum albumin conjugated variant of TWEAK (HSA-Flag-TWEAK), mimicking the activity of soluble TWEAK. Treatment with HSA-Flag-TWEAK resulted in significantly increased mortality in comparison to the placebo group due to myocardial rupture. Infarct size, extracellular matrix remodeling, and apoptosis rates were not different after MI. However, HSA-Flag-TWEAK treatment increased infiltration of proinflammatory cells into the myocardium. Accordingly, depletion of neutrophils prevented cardiac ruptures without modulating all-cause mortality.ConclusionTreatment of mice with HSA-Flag-TWEAK induces myocardial healing defects after experimental MI. This is mediated by an exaggerated neutrophil infiltration into the myocardium.

Hexokinases (HKs) catalyze the first step in glucose metabolism. Of the three mammalian 100-kDa HK isoforms, HKI and II can bind to mitochondria and protect against cell death. HKIII does not bind mitochondria, and little is known about its regulation or cytoprotective effects. We studied the regulation of HKIII at the transcriptional and protein levels and investigated its role in cellular protection.We show that like HKII, HKIII expression is regulated by hypoxia, but other factors that regulate HKII expression have no effect on HKIII levels. This transcriptional regulation is partially dependent on hypoxia-inducible factor (HIF) signaling. We also demonstrate regulation at the protein level, as mutations in putative N-terminal substrate binding residues altered C-terminal catalytic activity, suggesting that HKIII activity is governed, in part, by interactions between these two domains. Overexpression of HKIII reduced oxidant-induced cell death, increased ATP levels, decreased the production of reactive oxygen species (ROS), and preserved mitochondrial membrane potential. HKIII overexpression was also associated with higher levels of transcription factors that regulate mitochondrial biogenesis, and greater total mitochondrial DNA content. Attempts to target HKIII to the mitochondria by replacing its N-terminal 32-amino-acid sequence with the mitochondrial-targeting sequence of HKII led to protein aggregation, suggesting that this region is necessary to maintain proper protein folding and solubility.These results suggest that HKIII is regulated by hypoxia and there are functional interactions between its two halves. Furthermore, HKIII exerts protective effects against oxidative stress, perhaps by increasing ATP levels, reducing oxidant-induced ROS production, preserving mitochondrial membrane potential, and increasing mitochondrial biogenesis.

Background: Dysregulation of Fractalkine (CX3CL1) and its receptor CX3CR1 has been linked to the pathobiology of chronic inflammatory conditions. We explored CX3CL1 in systemic sclerosis (SSc) related progressive interstitial lung disease (ILD) and pulmonary hypertension (PH) in two different but complementary sources of biomaterial. Methods: We collected lung tissue at the time of lung transplantation at UCLA from SSc-ILD patients (n = 12) and healthy donors (n = 12); and serum samples from the prospective Oslo University Hospital SSc cohort (n = 292) and healthy donors (n = 100). CX3CL1 was measured by ELISA. Cellular sources of CX3CL1/CX3CR1 in lung tissues were determined by immunohistochemistry and immunofluorescence. ILD progression and new onset PH endpoints were analysed. Results: CX3CL1 concentrations were increased in SSc in lung tissue as well as in sera. In the UCLA cohort, CX3CL1 was highly correlated with DLCO. In the SSc-ILD lungs, CX3CL1 was identified in reactive type II pneumocytes and airway epithelial cells. CX3CR1 stained infiltrating interstitial mononuclear cells, especially plasma cells. In the Oslo cohort, CX3CL1 correlated with anti-Topoisomerase-I-antibody and lung fibrosis. CX3CL1 was associated with ILD progression in multivariable regression analysis but not PH. Conclusion: CX3CL1 is associated with progressive SSc-ILD but not SSc-PH. The CX3CR1/CX3CL1-biological axis may be involved in recruiting antibody secreting plasma cells to SSc lungs, thereby contributing to the immune-mediated pathobiology of SSc-ILD. [ABSTRACT FROM AUTHOR]