scholarly journals Pseudohypoxic HIF pathway activation dysregulates collagen structure-function in human lung fibrosis

2021 ◽  
Author(s):  
Christopher J Brereton ◽  
Liudi Yao ◽  
Yilu Zhou ◽  
Milica Vukmirovic ◽  
Joseph A Bell ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Structure Function ◽  
Lung Fibrosis ◽  
Human Lung ◽  
Ex Vivo ◽  
Fibrillar Collagen ◽  
Collagen Structure ◽  
Critical Pathway ◽  
Pathway Activation ◽  
Hif Pathway

Extracellular matrix (ECM) stiffening with downstream activation of mechanosensitive pathways is strongly implicated in fibrosis. We previously reported that altered collagen nanoarchitecture is a key determinant of pathogenetic ECM structure-function in human fibrosis (Jones et al., 2018). Here, through human tissue, bioinformatic and ex vivo studies we show that hypoxia-inducible factor (HIF) pathway activation is a critical pathway for this process regardless of oxygen status (pseudohypoxia). Whilst TGFβ increased rate of fibrillar collagen synthesis, HIF pathway activation was required to dysregulate post-translational modification of fibrillar collagen, promoting 'bone-type' cross-linking, altering collagen nanostructure, and increasing tissue stiffness. In vitro, knock down of Factor Inhibiting HIF (FIH) or oxidative stress caused pseudohypoxic HIF activation in normal fibroblasts. In contrast, endogenous FIH activity was reduced in fibroblasts from patients with lung fibrosis in association with significantly increased normoxic HIF pathway activation. In human lung fibrosis tissue, HIF mediated signalling was increased at sites of active fibrogenesis whilst subpopulations of IPF lung mesenchymal cells had increases in both HIF and oxidative stress scores. Our data demonstrate that oxidative stress can drive pseudohypoxic HIF pathway activation which is a critical regulator of pathogenetic collagen-structure function in fibrosis.

HIF pathway activation is a core regulator of collagen structure-function in lung fibrosis

2020 ◽  
Author(s):  
Christopher J Brereton ◽  
Robert Ridley ◽  
Franco Conforti ◽  
Liudi Yao ◽  
Aiman Alzetani ◽  
...  
Keyword(s):  
Structure Function ◽  
Lung Fibrosis ◽  
Collagen Structure ◽  
Pathway Activation ◽  
Hif Pathway

scholarly journals A validated hypoxia-inducible factor (HIF) signature across tissue compartments predicts clinical outcome in human lung fibrosis

2022 ◽  
Author(s):  
Yilu Zhou ◽  
Rob Ewing ◽  
Donna E. Davies ◽  
Yihua Wang ◽  
Mark Jones
Keyword(s):  
Oxidative Stress ◽  
Lung Fibrosis ◽  
Mononuclear Cells ◽  
Human Lung ◽  
Hypoxia Inducible Factor ◽  
Prognostic Significance ◽  
Gene Expression Signature ◽  
Pathway Activation ◽  
Tissue Compartments ◽  
Hif Pathway

We previously reported that oxidative stress drives pseudohypoxic hypoxia-inducible factor (HIF) pathway activation to promote pathogenetic collagen structure-function in human lung fibrosis (Brereton et al., 2022). Here, through bioinformatic studies we investigate HIF pathway activation status in patients with idiopathic pulmonary fibrosis (IPF) and whether this has prognostic significance. Applying a well-established HIF gene expression signature, we classified publicly available datasets into HIF score-high and score-low groups across multiple tissue compartments. TheHIF scores in lung tissue, bronchoalveolar lavage (BAL) and peripheral blood mononuclear cells (PBMC) were increased in IPF patients and significantly correlated with an oxidative stress signature consistent with pseudohypoxic HIF pathway activation. A high HIF score in BAL and in PBMC was a strong independent predictor of mortality in multivariate analysis. Thus, a validated HIF gene signature predicts survival across tissue compartments in IPF and merits prospective study as a non-invasive biomarker of lung fibrosis progression.

scholarly journals 2027 The role of lysyl oxidase in systemic sclerosis-associated lung fibrosis

2018 ◽  
Vol 2 (S1) ◽  
pp. 32-33
Author(s):  
Xinh-Xinh Nguyen ◽  
Tetsuya Nishimoto ◽  
Takahisa Takihara ◽  
Logan Mlakar ◽  
Ellen Riemer ◽  
...  
Keyword(s):  
Lung Fibrosis ◽  
Human Lung ◽  
Ex Vivo ◽  
Lysyl Oxidase ◽  
Lung Fibroblasts ◽  
Primary Fibroblasts ◽  
Expression And Activity

OBJECTIVES/SPECIFIC AIMS: Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology characterized by progressive fibrosis of the skin and multiple visceral organs. Effective therapies for SSc are needed. Lysyl oxidase (LOX) is a copper-dependent amide oxidase that plays a critical role in the crosslinking of the extracellular matrix (ECM). In this study, we investigated the role of LOX in the pathophysiology of SSc. METHODS/STUDY POPULATION: LOX expression and protein levels were measured in lung tissues and primary fibroblasts from patients with SSc and healthy controls. The effects of recombinant LOX (rLOX) were measured in vitro in primary fibroblasts, ex vivo in human lung tissues and in vivo in mice given bleomycin in combination with rLOX. LOX levels and activity were evaluated in lung fibroblasts treated with an endostatin-derived peptide that ameliorates fibrosis and in mice treated with bleomycin in combination with the peptide. Further, to differentiate the crosslinking activity of LOX from other potential effects, primary human fibroblasts were cultured with rLOX in the presence of the inhibitor, beta-aminopropionitrile. The expression levels of ECM (collagen and fibronectin), pro-fibrotic factors (IL-6 and TGF-beta), and transcription factor (c-Fos) were examined by real-time PCR, ELISA, immunoblotting, or hydroxyproline assay. RESULTS/ANTICIPATED RESULTS: LOX mRNA was increased in lung tissues and matching fibroblasts of SSc patients. rLOX-induced ECM production in vitro and ex vivo in lung fibroblasts and in human lung tissues maintained in organ culture, respectively. Additionally, TGF-beta and bleomycin induced ECM production, LOX mRNA expression and activity. Endostatin peptide abrogated these effects. In vivo, rLOX synergistically exacerbated pulmonary fibrosis in bleomycin-treated mice. The inhibition of LOX catalytic activity by beta-aminopropionitrile failed to abrogate LOX-induced ECM production. LOX increased the production of IL-6. IL-6 neutralization blocked the effects of LOX. Further, LOX induced c-Fos expression and its nuclear localization. DISCUSSION/SIGNIFICANCE OF IMPACT: LOX expression and activity were increased with fibrosis in vitro, ex vivo, and in vivo. LOX induced fibrosis via increasing ECM, IL-6 and c-Fos translocation to the nucleus. These effects were independent of the crosslinking activity of LOX and mediated by IL-6. Our findings suggest that inhibition of LOX may be a viable option for the treatment of lung fibrosis. Further, the use of human lung in organ culture establishes the relevance of our findings to human disease.

scholarly journals Nanoscale dysregulation of collagen structure-function disrupts mechano-homeostasis and mediates pulmonary fibrosis

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Mark G Jones ◽  
Orestis G Andriotis ◽  
James JW Roberts ◽  
Kerry Lunn ◽  
Victoria J Tear ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Structure Function ◽  
Ex Vivo ◽  
Lysyl Oxidase ◽  
Cross Linking ◽  
Collagen Structure ◽  
Tissue Stiffness ◽  
Collagen Concentration ◽  
Dual Inhibition

Matrix stiffening with downstream activation of mechanosensitive pathways is strongly implicated in progressive fibrosis; however, pathologic changes in extracellular matrix (ECM) that initiate mechano-homeostasis dysregulation are not defined in human disease. By integrated multiscale biomechanical and biological analyses of idiopathic pulmonary fibrosis lung tissue, we identify that increased tissue stiffness is a function of dysregulated post-translational collagen cross-linking rather than any collagen concentration increase whilst at the nanometre-scale collagen fibrils are structurally and functionally abnormal with increased stiffness, reduced swelling ratio, and reduced diameter. In ex vivo and animal models of lung fibrosis, dual inhibition of lysyl oxidase-like (LOXL) 2 and LOXL3 was sufficient to normalise collagen fibrillogenesis, reduce tissue stiffness, and improve lung function in vivo. Thus, in human fibrosis, altered collagen architecture is a key determinant of abnormal ECM structure-function, and inhibition of pyridinoline cross-linking can maintain mechano-homeostasis to limit the self-sustaining effects of ECM on progressive fibrosis.

scholarly journals Hyperhomocysteinemia exacerbates ischemia-reperfusion injury-induced acute kidney injury by mediating oxidative stress, DNA damage, JNK pathway, and apoptosis

2021 ◽  
Vol 16 (1) ◽  
pp. 537-543
Author(s):  
Mei Zhang ◽  
Jing Yuan ◽  
Rong Dong ◽  
Jingjing Da ◽  
Qian Li ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Cell Apoptosis ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Kidney Injury ◽  
Tubular Cell ◽  
Tubular Injury ◽  
Jnk Pathway ◽  
Pathway Activation

Abstract Background Hyperhomocysteinemia (HHcy) plays an important role in the progression of many kidney diseases; however, the relationship between HHcy and ischemia-reperfusion injury (IRI)-induced acute kidney injury (IRI-induced AKI) is far from clear. In this study, we try to investigate the effect and possible mechanisms of HHcy on IRI-induced AKI. Methods Twenty C57/BL6 mice were reared with a regular diet or high methionine diet for 2 weeks (to generate HHcy mice); after that, mice were subgrouped to receive sham operation or ischemia-reperfusion surgery. Twenty four hour after reperfusion, serum creatinine, blood urea nitrogen, and Malondialdehyde (MDA) were measured. H&E staining for tubular injury, western blot for γH2AX, JNK, p-JNK, and cleaved caspase 3, and TUNEL assay for tubular cell apoptosis were also performed. Results Our results showed that HHcy did not influence the renal function and histological structure, as well as the levels of MDA, γH2AX, JNK, p-JNK, and tubular cell apoptosis in control mice. However, in IRI-induced AKI mice, HHcy caused severer renal dysfunction and tubular injury, higher levels of oxidative stress, DNA damage, JNK pathway activation, and tubular cell apoptosis. Conclusion Our results demonstrated that HHcy could exacerbate IRI-induced AKI, which may be achieved through promoting oxidative stress, DNA damage, JNK pathway activation, and consequent apoptosis.

scholarly journals Coptisine Attenuates Diabetes—Associated Endothelial Dysfunction through Inhibition of Endoplasmic Reticulum Stress and Oxidative Stress

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4210
Author(s):  
Yan Zhou ◽  
Chunxiu Zhou ◽  
Xutao Zhang ◽  
Chi Teng Vong ◽  
Yitao Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Risk Factors ◽  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Vascular Function ◽  
Inflammatory Responses ◽  
Therapeutic Potential ◽  
Ex Vivo ◽  
Diabetic Mice ◽  
And Oxidative Stress

Coptisine is the major bioactive protoberberine alkaloid found in Rhizoma Coptidis. Coptisine reduces inflammatory responses and improves glucose tolerance; nevertheless, whether coptisine has vasoprotective effect in diabetes is not fully characterized. Conduit arteries including aortas and carotid arteries were obtained from male C57BL/6J mice for ex vivo treatment with risk factors (high glucose or tunicamycin) and coptisine. Some arterial rings were obtained from diabetic mice, which were induced by high-fat diet (45% kcal% fat) feeding for 6 weeks combined with a low-dose intraperitoneal injection of streptozotocin (120 mg/kg). Functional studies showed that coptisine protected endothelium-dependent relaxation in aortas against risk factors and from diabetic mice. Coptisine increased phosphorylations of AMPK and eNOS and downregulated the endoplasmic reticulum (ER) stress markers as determined by Western blotting. Coptisine elevates NO bioavailability and decreases reactive oxygen species level. The results indicate that coptisine improves vascular function in diabetes through suppression of ER stress and oxidative stress, implying the therapeutic potential of coptisine to treat diabetic vasculopathy.

scholarly journals Oxidative stress response in regulatory and conventional T cells: a comparison between patients with chronic coronary syndrome and healthy subjects

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Anna K. Lundberg ◽  
Rosanna W. S. Chung ◽  
Louise Zeijlon ◽  
Gustav Fernström ◽  
Lena Jonasson
Keyword(s):  
Oxidative Stress ◽  
T Cells ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Thioredoxin Reductase ◽  
Healthy Controls ◽  
Antioxidant Genes ◽  
Consistent Finding ◽  
Coronary Syndrome ◽  
Thioredoxin Reductase 1

Abstract Background Inflammation and oxidative stress form a vicious circle in atherosclerosis. Oxidative stress can have detrimental effects on T cells. A unique subset of CD4+ T cells, known as regulatory T (Treg) cells, has been associated with atheroprotective effects. Reduced numbers of Treg cells is a consistent finding in patients with chronic coronary syndrome (CCS). However, it is unclear to what extent these cells are sensitive to oxidative stress. In this pilot study, we tested the hypothesis that oxidative stress might be a potential contributor to the Treg cell deficit in CCS patients. Methods Thirty patients with CCS and 24 healthy controls were included. Treg (CD4+CD25+CD127−) and conventional T (CD4+CD25−, Tconv) cells were isolated and treated with increasing doses of H2O2. Intracellular ROS levels and cell death were measured after 2 and 18 h, respectively. The expression of antioxidant genes was measured in freshly isolated Treg and Tconv cells. Also, total antioxidant capacity (TAC) was measured in fresh peripheral blood mononuclear cells, and oxidized (ox) LDL/LDL ratios were determined in plasma. Results At all doses of H2O2, Treg cells accumulated more ROS and exhibited higher rates of death than their Tconv counterparts, p < 0.0001. Treg cells also expressed higher levels of antioxidant genes, including thioredoxin and thioredoxin reductase-1 (p < 0.0001), though without any differences between CCS patients and controls. Tconv cells from CCS patients were, on the other hand, more sensitive to oxidative stress ex vivo and expressed more thioredoxin reductase-1 than Tconv cells from controls, p < 0.05. Also, TAC levels were lower in patients, 0.97 vs 1.53 UAE/100 µg, p = 0.001, while oxLDL/LDL ratios were higher, 29 vs 22, p = 0.006. Conclusion Treg cells isolated from either CCS patients or healthy controls were all highly sensitive to oxidative stress ex vivo. There were signs of oxidant-antioxidant imbalance in CCS patients and we thus assume that oxidative stress may play a role in the reduction of Treg cells in vivo.

scholarly journals Cardioprotective Effects of PPARβ/δ Activation against Ischemia/Reperfusion Injury in Rat Heart Are Associated with ALDH2 Upregulation, Amelioration of Oxidative Stress and Preservation of Mitochondrial Energy Production

2021 ◽  
Vol 22 (12) ◽  
pp. 6399
Author(s):  
Ioanna Papatheodorou ◽  
Eleftheria Galatou ◽  
Georgios-Dimitrios Panagiotidis ◽  
Táňa Ravingerová ◽  
Antigone Lazou
Keyword(s):  
Oxidative Stress ◽  
Mrna Expression ◽  
Energy Production ◽  
Citrate Synthase ◽  
Ischemia Reperfusion Injury ◽  
Ex Vivo ◽  
Uncoupling Protein ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Isocitrate Dehydrogenase 2

Accumulating evidence support the cardioprotective properties of the nuclear receptor peroxisome proliferator activated receptor β/δ (PPARβ/δ); however, the underlying mechanisms are not yet fully elucidated. The aim of the study was to further investigate the mechanisms underlying PPARβ/δ-mediated cardioprotection in the setting of myocardial ischemia/reperfusion (I/R). For this purpose, rats were treated with PPARβ/δ agonist GW0742 and/or antagonist GSK0660 in vivo and hearts were subjected to ex vivo global ischemia followed by reperfusion. PPARβ/δ activation improved left ventricular developed pressure recovery, reduced infarct size (IS) and incidence of reperfusion-induced ventricular arrhythmias while it also up-regulated superoxide dismutase 2, catalase and uncoupling protein 3 resulting in attenuation of oxidative stress as evidenced by the reduction in 4-hydroxy-2-nonenal protein adducts and protein carbonyl formation. PPARβ/δ activation also increased both mRNA expression and enzymatic activity of aldehyde dehydrogenase 2 (ALDH2); inhibition of ALDH2 abrogated the IS limiting effect of PPARβ/δ activation. Furthermore, upregulation of PGC-1α and isocitrate dehydrogenase 2 mRNA expression, increased citrate synthase activity as well as mitochondrial ATP content indicated improvement in mitochondrial content and energy production. These data provide new mechanistic insight into the cardioprotective properties of PPARβ/δ in I/R pointing to ALDH2 as a direct downstream target and suggesting that PPARβ/δ activation alleviates myocardial I/R injury through coordinated stimulation of the antioxidant defense of the heart and preservation of mitochondrial function.

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