Downregulation of epithelial DUOX1 in Chronic Obstructive Pulmonary Disease contributes to disease pathogenesis

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Abstract

COPD is a chronic respiratory disease characterized by small airway remodeling and alveolar emphysema due to environmental stresses such as cigarette smoking (CS). Oxidative stress is commonly implicated in COPD pathology, but recent findings suggest that one oxidant-producing NADPH oxidase homolog, dual oxidase 1 (DUOX1), is downregulated in the airways of COPD patients. We evaluated lung tissue sections from COPD patients for small airway epithelial DUOX1 protein expression, in association with measures of lung function and small airway and alveolar remodeling. We also addressed the impact of DUOX1 for lung tissue remodeling in mouse models of COPD. Small airway DUOX1 levels were decreased in advanced COPD, and correlated with loss of lung function and markers of emphysema and remodeling. Similarly, DUOX1 downregulation in correlation with extracellular matrix remodeling was observed in a genetic model of COPD, transgenic SPC-TNF-α mice. Finally, development of subepithelial airway fibrosis in mice due to exposure to the CS-component acrolein, or alveolar emphysema induced by administration of elastase, were in both cases exacerbated in Duox1-deficient mice. Collectively, our studies highlight that downregulation of DUOX1 may be a contributing feature of COPD pathogenesis, likely related to impaired DUOX1-mediated innate injury responses involved in epithelial homeostasis.

Authors

Caspar Schiffers, Cheryl van de Wetering, Robert A. Bauer, Aida Habibovic, Milena Hristova, Christopher M. Dustin, Sara Lambrichts, Pamela M. Vacek, Emiel F.M. Wouters, Niki L. Reynaert, Albert van der Vliet

CD4⁺CD25⁺CD127^hi cell frequency predicts disease progression in type 1 diabetes

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Abstract

Transient partial remission, a period of low insulin requirement experienced by most patients soon after diagnosis has been associated with mechanisms of immune regulation. A better understanding of such natural mechanisms of immune regulation might identify new targets for immunotherapies that reverse T1D. In this study, using Cox model multivariate analysis we validate our previous findings that patients (n = 84) with the highest frequency of CD4+ CD25+CD127hi (127-hi) cells at diagnosis experience the longest partial remission and we show that the 127-hi cell population is a mix of Th1- and Th2-type cells with a significant bias towards anti-inflammatory Th2-type cells. In addition, we extend these findings to show that patients with the highest frequency of 127-hi cells at diagnosis are significantly more likely to maintain beta-cell function. Moreover, in patients treated with Alefacept in the TIDAL clinical trial, the probability of responding favorably to the anti-inflammatory drug was significantly higher in those with a higher frequency of 127-hi cells at diagnosis than those with a lower 127-hi cell frequency. These data are consistent with the hypothesis that 127-hi cells maintain an anti-inflammatory environment that is permissive for partial remission, beta-cell survival and response to anti-inflammatory immunotherapy.

Authors

Aditi Narsale, Breanna Lam, Rosita Moya, TingTing Lu, Alessandra Mandelli, Irene Gotuzzo, Benedetta Pessina, Gian Maria Giamporcaro, Rhonda Geoffrey, Kerry Buchanan, Mark Harris, Anne-Sophie Bergot, Ranjeny Thomas, Martin J. Hessner, Manuela Battaglia, Elisavet Serti, Joanna D. Davies

STOX1 deficiency is associated with renin-mediated gestational hypertension and placental defects

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Abstract

The pathogenesis of preeclampsia and other hypertensive disorders of pregnancy remains poorly-defined despite the substantial burden of maternal and neonatal morbidity associated with these conditions. In particular, the role of genetic variants as determinants of disease susceptibility remains unknown. Storkhead-box protein 1 (STOX1) was first identified as a preeclampsia risk gene through family-based genetic linkage studies in which loss-of-function variants were proposed to underlie increased preeclampsia susceptibility. We generated a genetic Stox1 loss-of-function mouse model (Stox1 KO), to evaluate whether STOX1 regulates blood pressure in pregnancy. Pregnant Stox1 KO mice developed gestational hypertension evidenced by a significant increase in blood pressure compared with wild type by E17.5. While severe renal, placental, or fetal growth abnormalities were not observed, the Stox1 KO phenotype was associated with placental vascular and extracellular matrix abnormalities. Mechanistically, we found that gestational hypertension in Stox1 KO mice resulted from activation of the uteroplacental renin-angiotensin system. We confirmed this mechanism by showing that treatment of pregnant Stox1 KO mice with an angiotensin II receptor blocker rescued the phenotype. Our study demonstrates the utility of genetic mouse models for uncovering links between genetic variants and effector pathways implicated in the pathogenesis of hypertensive disorders of pregnancy.

Authors

Jacqueline G. Parchem, Keizo Kanasaki, Soo Bong Lee, Megumi Kanasaki, Joyce L. Yang, Yong Xu, Kadeshia M. Earl, Rachel A. Keuls, Vincent H. Gattone, Raghu Kalluri

Identifying a biological signature of prenatal maternal stress

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Abstract

Psychological stress affects maternal gastrointestinal (GI) permeability, leading to low-grade inflammation which can impact negatively on fetal development. We investigated a panel of circulating markers as a biological signature of this stress exposure in pregnant women with and without the stress-related GI disorder irritable bowel syndrome (IBS). Markers of GI permeability and inflammation were measured in plasma from healthy (n = 104) and IBS cohorts (n = 105) of women at 15- and 20-weeks’ gestation. Biomarkers were evaluated with respect to their degree of association to levels of stress, anxiety and depression as indicated by responses from the Perceived Stress Scale, State-Trait Anxiety Inventory and Edinburgh Postnatal Depression Scale. High levels of stress were associated with elevations of soluble CD14, lipopolysaccharide binding protein (LBP) and tumour necrosis factor-α, while anxiety associated with elevated concentrations of C-reactive protein (CRP) in otherwise healthy pregnancies. Prenatal depression was associated with higher levels of soluble CD14, LBP and CRP in the healthy cohort. High levels of prenatal anxiety and depression were also associated with lower concentrations of tryptophan and kynurenine respectively in the IBS cohort. These markers may represent a core maternal biological signature of active prenatal stress which can be used to inform intervention strategies via stress reduction techniques or other lifestyle approaches. Such interventions may need to be tailored to reflect underlying GI conditions such as IBS.

Authors

James M. Keane, Ali S. Khashan, Fergus P. McCarthy, Louise C. Kenny, James M. Collins, Sarah M. O’Donovan, Jillian R.M. Brown, John F. Cryan, Timothy G. Dinan, Gerard Clarke, Siobhain M. O'Mahony

Impaired muscle mitochondrial energetics is associated with uremic metabolite accumulation in chronic kidney disease

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Abstract

Chronic kidney disease (CKD) results in a progressive skeletal myopathy involving atrophy, weakness, and fatigue. Mitochondria have been thought to contribute to skeletal myopathy, however, the molecular mechanisms underlying changes in muscle metabolism in CKD are unknown. This study employed a comprehensive mitochondrial phenotyping platform to elucidate the mechanisms of skeletal muscle mitochondrial impairment in mice with adenine-induced CKD. CKD mice displayed significant reductions in mitochondrial oxidative phosphorylation (OXPHOS), which was strongly correlated with glomerular filtration rate, suggesting a link between kidney function and muscle mitochondrial health. Biochemical assays uncovered that OXPHOS dysfunction was driven principally by reduced activity of matrix dehydrogenases. Untargeted metabolomics analyses in skeletal muscle revealed a distinct metabolite profile in CKD muscle including accumulation of uremic toxins that strongly associated with the degree of mitochondrial impairment. Additional muscle phenotyping found that CKD mice experienced muscle atrophy and increased muscle protein degradation, but only male CKD mice had lower maximal contractile force. CKD mice also had morphological changes indicative of destabilization in the neuromuscular junction. This study provides the first comprehensive evaluation of mitochondrial health in murine CKD muscle and uncovers several unknown uremic metabolites that are strongly associated with the degree of mitochondrial impairment.

Authors

Trace Thome, Ravi A. Kumar, Sarah K. Burke, Ram B. Khattri, Zachary R. Salyers, Rachel C. Kelley, Madeline D. Coleman, Demetra D. Christou, Russell T. Hepple, Salvatore T. Scali, Leonardo F. Ferreira, Terence E. Ryan

MicroRNA miR-24-3p reduces DNA damage responses, apoptosis, and susceptibility to chronic obstructive pulmonary disease

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Abstract

The pathogenesis of Chronic Obstructive Pulmonary Disease (COPD) involves aberrant responses to cellular stress caused by chronic cigarette smoke (CS) exposure. However, not all smokers develop COPD and the critical mechanisms that regulate cellular stress responses to increase COPD susceptibility are not understood. Because microRNAs are well-known regulators of cellular stress responses, we evaluated microRNA expression arrays performed on distal parenchymal lung tissue samples from 172 subjects with and without COPD. We identified miR-24-3p as the microRNA that best correlated with radiographic emphysema (ρ=-0.353, P=1.3e-04), and validated this finding in multiple cohorts. In a CS-exposure mouse model, inhibition of miR-24-3p increased susceptibility to apoptosis, including alveolar type II epithelial cell (AECII) apoptosis, and emphysema severity. In lung epithelial cells, miR-24-3p suppressed apoptosis through the BH3-only protein BIM and suppressed homology-directed DNA repair and the DNA repair protein BRCA1. Finally, we found BIM and BRCA1 are increased in COPD lung tissue, and BIM and BRCA1 expression inversely correlate with miR-24-3p. We concluded that miR-24-3p, a regulator of the cellular response to DNA damage, is decreased in COPD, and decreased miR-24-3p increases susceptibility to emphysema through increased BIM and apoptosis.

Authors

Jessica Nouws, Feng Wan, Eric Finnemore, Willy Roque, So-Jin Kim, Isabel S. Bazan, Chuan-Xing Li, C. Magnus Sköld, Qile Dai, Xiting Yan, Maurizio Chioccioli, Veronique Neumeister, Clemente J. Britto, Joann Sweasy, Ranjit S. Bindra, Åsa M. Wheelock, Jose L. Gomez, Naftali Kaminski, Patty J. Lee, Maor Sauler

BRD4 inhibition and FXR activation, individually beneficial in cholestasis, are antagonistic in combination

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Abstract

Activation of Farnesoid-X-Receptor (FXR) by obeticholic acid (OCA) reduces hepatic inflammation and fibrosis in patients with primary biliary cholangitis (PBC), a life-threatening cholestatic liver failure. Inhibition of bromodomain-containing protein-4 (BRD4) also has anti-inflammatory, anti-fibrotic effects in mice. We determined the role of BRD4 in FXR function in bile acid (BA) regulation and examined whether the known beneficial effects of OCA are enhanced by inhibiting BRD4 in cholestatic mice. Liver-specific downregulation of BRD4 disrupted BA homeostasis in mice, and FXR-mediated regulation of BA-related genes, including Shp and Cyp7a1, was BRD4-dependent. In cholestatic mice, JQ1 or OCA treatment ameliorated hepatotoxicity, inflammation, and fibrosis, but surprisingly, was antagonistic in combination. Mechanistically, OCA increased binding of FXR and the corepressor SMRT, decreased NF-κB binding at inflammatory genes, and repressed the genes in a BRD4-dependent manner. In PBC patients, hepatic expression of FXR and BRD4 was significantly reduced. In conclusion, BRD4 is a novel cofactor of FXR for maintaining BA homeostasis and hepatoprotection. While BRD4 promotes hepatic inflammation and fibrosis in cholestasis, paradoxically, BRD4 is required for the anti-inflammatory, anti-fibrotic actions of OCA-activated FXR. Co-treatment with OCA and JQ1, individually beneficial, may be antagonistic in treatment of liver disease patients with inflammation and fibrosis complications.

Authors

Hyunkyung Jung, Jinjing Chen, Xiangming Hu, Hao Sun, Shwu-Yuan Wu, Cheng-Ming Chiang, Byron Kemper, Lin-Feng Chen, Jongsook Kemper

Early brainstem ^[18F]THK5351 uptake is linked to cortical hyper-excitability in healthy aging

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Abstract

Background. Neuronal hyper-excitability characterizes the early stages of Alzheimer’s disease (AD). In animals, early misfolded tau and amyloid-beta (Aβ) protein accumulation, both central to AD neuropathology, promote cortical excitability and neuronal network dysfunction. In healthy humans, misfolded tau and Aβ aggregates are first detected, respectively, in the brainstem and frontomedial and temporobasal cortices, decades prior to the onset of AD cognitive symptoms. Whether cortical excitability is related to early brainstem tau, and its associated neuroinflammation, and cortical Aβ aggregations remains unknown. Methods. We probed frontal cortex excitability, using transcranial magnetic stimulation combined with electroencephalography, in a sample of 64 healthy late middle-aged individuals (50-69 y; 45 women). We assessed whole-brain [18F]THK5351 positron emission tomography (PET) uptake as a proxy measure of tau/neuroinflammation, and whole-brain Aβ burden with [18F]Flutemetamol or [18F]Florbetapir radiotracers. Results. We find that higher [18F]THK5351 uptake in a brainstem monoaminergic compartment is associated with increased cortical excitability (r = .29, p = .02). By contrast, [18F]THK5351 PET signal in the hippocampal formation, although strongly correlated with brainstem signal in whole-brain voxel-based quantification analyses (pFWE-corrected < .001), was not significantly associated with cortical excitability (r = .14, p = .25). Importantly, no significant association was found between early Aβ cortical deposits and cortical excitability (r = -.20, p = .11). Conclusion. These findings reveal potential brain substrates for increased cortical excitability in preclinical AD and may constitute functional in vivo correlates of early brainstem tau accumulation and neuroinflammation in humans. Trial registration. EudraCT 2016-001436-35. Funding. F.R.S.-FNRS Belgium, Wallonie-Bruxelles International, ULiège, Fondation Simone et Pierre Clerdent, European Regional Development Fund.

Authors

Maxime Van Egroo, Daphne O. Chylinski, Justinas Narbutas, Gabriel Besson, Vincenzo Muto, Christina Schmidt, Davide Marzoli, Paolo Cardone, Nora Vandeleene, Martin Grignard, André Luxen, Eric Salmon, Christian Lambert, Christine Bastin, Fabienne Collette, Christophe Phillips, Pierre Maquet, Mohamed Ali Bahri, Evelyne Balteau, Gilles Vandewalle

Loss of Fas-signaling in fibroblasts impairs homeostatic fibrosis resolution and promotes persistent pulmonary fibrosis

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Abstract

Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible fibrotic disease of the distal lung alveoli that culminates in respiratory failure and reduced lifespan. Unlike normal lung repair in response to injury, IPF is associated with the accumulation and persistence of fibroblasts and myofibroblasts and continued production of collagen and other extracellular matrix (ECM) components. Prior in vitro studies have led to the hypothesis that the development of resistance to Fas-induced apoptosis by lung fibroblasts and myofibroblasts contibributes to their accumulation in the distal lung tissues of IPF patients. Here, we test this hypothesis in vivo in the resolving model of bleomycin-induced pulmonary fibrosis in mice. Using genetic loss-of-function approaches to inhibit Fas signaling in fibroblasts, novel flow cytometry strategies to quantify lung fibroblast subsets and transcriptional profiling of lung fibroblasts by bulk and single cell RNA-sequencing, we show that Fas is necessary for lung fibroblast apoptosis during homeostatic resolution of bleomycin-induced pulmonary fibrosis in vivo. Furthermore, we show that loss of Fas signaling leads to the persistence and continued pro-fibrotic functions of lung fibroblasts. Our studies provide novel insights into the mechanisms that contribute to fibroblast survival, persistence and continued ECM deposition in the context of IPF and how failure to undergo Fas-induced apoptosis prevents fibrosis resolution.

Authors

Elizabeth F. Redente, Sangeeta Chakraborty, Satria P. Sajuthi, Bart P. Black, Ben L. Edelman, Max A. Seibold, David W.H. Riches

Estradiol resolves pneumonia via ER-β regulatory T cells

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Abstract

Current treatments for pneumonia (PNA) are focused on the pathogens. Mortality from PNA-induced acute lung injury (PNA-ALI) remains high, underscoring the need for additional therapeutic targets. Clinical and experimental evidence exists for potential sex differences in PNA survival, with males having higher mortality. In a model of severe pneumococcal PNA, when compared to males, age-matched female mice exhibited enhanced resolution characterized with decreased alveolar and lung inflammation and increased numbers of Regulatory T cells (Tregs). Recognizing the critical role of Tregs in lung injury resolution, we evaluated if improved outcomes in females were due to estradiol (E2) effects on Treg biology. E2 promoted Treg suppressive phenotype in vitro and resolution of PNA in vivo. Systemic rescue administration of E2 promoted resolution of PNA in males independent of lung bacterial clearance. E2 augmented Treg expression of Foxp3, CD25 and GATA3, an effect that required ERb, and not ERa signaling. Importantly, the in vivo therapeutic effects of E2 were lost in Treg depleted mice (Foxp3DTR). Adoptive transfer of ex vivo E2-treated Tregs rescued S. pneumoniae-induce PNA-ALI, a salutary effect that required Treg ERβ expression. E2-ERβ was required for Tregs to control macrophage pro-inflammatory responses. Our findings support the therapeutic role for E2 in promoting resolution of lung inflammation after PNA via ERβ Tregs.

Authors

Ye Xiong, Qiong Zhong, Tsvi Palmer, Alison Benner, Lan Wang, Karthik Suresh, Rachel Damico, Franco R. D'Alessio