The copper chelator tetrathiomolybdate regressed bleomycin-induced pulmonary fibrosis in mice, by reducing lysyl oxidase expressions

Copper homeostasis dysregulation in respiratory diseases: a review of current knowledge

Cu is an essential micronutrient for various physiological processes in almost all human cell types. Given the critical role of Cu in a wide range of cellular processes, the local concentrations of Cu and the cellular distribution of Cu transporter proteins in the lung are essential for maintaining a steady-state internal environment. Dysfunctional Cu metabolism or regulatory pathways can lead to an imbalance in Cu homeostasis in the lungs, affecting both acute and chronic pathological processes. Recent studies have identified a new form of Cu-dependent cell death called cuproptosis, which has generated renewed interest in the role of Cu homeostasis in diseases. Cuproptosis differs from other known cell death pathways. This occurs through the direct binding of Cu ions to lipoylated components of the tricarboxylic acid cycle during mitochondrial respiration, leading to the aggregation of lipoylated proteins and the subsequent downregulation of Fe-S cluster proteins, which causes toxic stress to the proteins and ultimately leads to cell death. Here, we discuss the impact of dysregulated Cu homeostasis on the pathogenesis of various respiratory diseases, including asthma, chronic obstructive pulmonary disease, idiopathic interstitial fibrosis, and lung cancer. We also discuss the therapeutic potential of targeting Cu. This study highlights the intricate interplay between copper, cellular processes, and respiratory health. Copper, while essential, must be carefully regulated to maintain the delicate balance between necessity and toxicity in living organisms. This review highlights the need to further investigate the precise mechanisms of copper interactions with infections and immune inflammation in the context of respiratory diseases and explore the potential of therapeutic strategies for copper, cuproptosis, and other related effects.

Bioinformatics-based dynamics of cuproptosis -related indicators in experimental silicosis

Pneumoconiosis is one of the most serious occupational diseases worldwide. Silicosis due to prolonged inhalation of free silica dust during occupational activities is one of the main types. Cuproptosis is a newly discovered mode of programmed cell death characterized by the accumulation of free copper in the cell, which ultimately leads to cell death. Increased copper in the serum of silicosis patients, suggests that the development of silicosis is accompanied by changes in copper metabolism, but whether cuproptosis is involved in the progression of silicosis is actually to be determined. To test this hypothesis, we screened the genetic changes in patients with idiopathic fibrosis by bioinformatics methods and predicted and functionally annotated the cuproptosis-related genes among them. Subsequently, we established a mouse silicosis model and detected the concentration of copper ions and the activity of ceruloplasmin (CP) in serum, as well as changes of the concentration of copper and cuproptosis related genes in mouse lung tissues. We identified 9 cuproptosis-related genes among the differential genes in patients with IPF at different times and the tissue-specific expression levels of ferredoxin 1 (FDX1) and Lipoyl synthase (LIAS) proteins. Furthermore, serum CP activity and copper ion levels in silicosis mice were elevated on days 7th and 56th after silica exposure. The expression of CP in mouse lung tissue elevated at all stages after silica exposure. The mRNA level of FDX1 decreased on days 7th and 56th, and the protein level remained in accordance with the mRNA level on day 56th. LIAS and Dihydrolipoamide dehydrogenase (DLD) levels were downregulated at all times after silica exposure. In addition, Heatshockprotein70 (HSP70) expression was increased on day 56. In brief, our results demonstrate that there may be cellular cuproptosis during the development of experimental silicosis in mice and show synchronization with enhanced copper loading in mice.

Identification and validation of mutual hub genes in idiopathic pulmonary fibrosis and rheumatoid arthritis-associated usual interstitial pneumonia

Objectives

The study aims at exploring common hub genes and pathways in idiopathic pulmonary fibrosis (IPF) and rheumatoid arthritis-associated usual interstitial pneumonia (RA-UIP) through integrated bioinformatics analyses.

Methods

The GSE199152 dataset containing lung tissue samples from IPF and RA-UIP patients was acquired from the Gene Expression Omnibus (GEO) database. The identification of overlapping differentially expressed genes (DEGs) in IPF and RA-UIP was carried out through R language. Protein-protein interaction (PPI) network analysis and module analysis were applied to filter mutual hub genes in the two diseases. Enrichment analyses were also conducted to analyze the possible biological functions and pathways of the overlapped DEGs and hub genes. The diagnostic value of key genes was assessed with R language, and the expressions of these genes in pulmonary cells of IPF and rheumatoid arthritis-associated interstitial lung disease (RA-ILD) patients were analyzed with single cell RNA-sequencing (scRNA-seq) datasets. The expression levels of hub genes were validated in blood samples from patients, specimens of human lung fibroblasts, lung tissue samples from mice, as well as external GEO datasets.

Results

Four common hub genes (THBS2, TIMP1, POSTN, and CD19) were screened. Enrichment analyses showed that the abnormal expressions of DEGs and hub genes may be connected with the onset of IPF and RA-UIP by regulating the progression of fibrosis. ScRNA-seq analyses illustrated that for both IPF and RA-ILD patients, THBS2, TIMP1, and POSTN were mainly expressed in lung fibroblasts, while CD19 was uniquely high-expressed in B cells. The qRT-PCR and immunohistochemistry (IHC) results verified that the expression levels of hub genes were mostly in accordance with the findings obtained from the bioinformatics analyses.

Conclusion

Though IPF and RA-UIP are distinct diseases, they may to some extent have mutual pathogenesis in the development of fibrosis. THBS2, TIMP1, POSTN, and CD19 may be the potential biomarkers of IPF and RA-UIP, and intervention on related pathways of these genes could offer new strategies for the precision treatment of IPF and RA-UIP.

The molecular mechanism underlying dermatomyositis related interstitial lung disease: evidence from bioinformatic analysis and in vivo validation

Background

Dermatomyositis (DM) is an autoimmune and inflammatory disease that can affect the lungs, causing interstitial lung diseases (ILD). However, the exact pathophysiological mechanisms underlying DM-ILD are unknown. Idiopathic pulmonary fibrosis (IPF) belongs to the broader spectrum of ILD and evidence shows that common pathologic pathways might lie between IPF and DM-ILD.

Methods

We retrieved gene expression profiles of DM and IPF from the Gene Expression Omnibus (GEO) and utilized weighted gene co-expression network analysis (WGCNA) to reveal their co-expression modules. We then performed a differentially expressed gene (DEG) analysis to identify common DEGs. Enrichment analyses were employed to uncover the hidden biological pathways. Additionally, we conducted protein-protein interaction (PPI) networks analysis, cluster analysis, and successfully found the hub genes, whose levels were further validated in DM-ILD patients. We also examined the relationship between hub genes and immune cell abundance in DM and IPF. Finally, we conducted a common transcription factors (TFs)-genes network by NetworkAnalyst.

Results

WGCNA revealed 258 intersecting genes, while DEG analysis identified 66 shared genes in DM and IPF. All of these genes were closely related to extracellular matrix and structure, cell-substrate adhesion, and collagen metabolism. Four hub genes (POSTN, THBS2, COL6A1, and LOXL1) were derived through intersecting the top 30 genes of the WGCNA and DEG sets. They were validated as active transcripts and showed diagnostic values for DM and IPF. However, ssGSEA revealed distinct infiltration patterns in DM and IPF. These four genes all showed a positive correlation with immune cells abundance in DM, but not in IPF. Finally, we identified one possible key transcription factor, MYC, that interact with all four hub genes.

Conclusion

Through bioinformatics analysis, we identified common hub genes and shared molecular pathways underlying DM and IPF, which provides valuable insights into the intricate mechanisms of these diseases and offers potential targets for diagnostic and therapeutic interventions.

Ammonium tetrathiomolybdate relieves oxidative stress in cisplatin-induced acute kidney injury via NRF2 signaling pathway

Cisplatin is an efficient chemotherapeutic agent for various solid tumors, but its usage is restricted by nephrotoxicity. A single dose of cisplatin can cause acute kidney injury (AKI), which is characterized by rapid reduction in kidney function. However, the current therapies, such as hydration, are limited. It is vital to develop novel therapeutic reagents that have both anticancer and renoprotective properties. The objective of this study was to determine whether ammonium tetrathiomolybdate (TM), a copper chelator used to treat cancer and disorders of copper metabolism, may offer protection against cisplatin-induced AKI. In this study, we demonstrated that TM treatment had antioxidative effects and mitigated cisplatin-induced AKI both in vivo and in vitro. Mechanically, TM inhibited NRF2 ubiquitination, which activated the NRF2 pathway in HK-2 cells and promoted the expression of target genes. It should be noted that the protective effect conferred by TM against cisplatin was compromised by the knockdown of the NRF2 gene. Furthermore, TM selectively activated the NRF2 pathways in the liver and kidney. The current study provided evidence for additional clinical applications of TM by showing that it activates NRF2 and has a favorable therapeutic impact on cisplatin-induced AKI.

Comparative transcription profiling of mRNA and lncRNA in pulmonary arterial hypertension after C75 treatment

OBJECTIVES

To investigate mRNA and long non-coding RNA (lncRNA) expression profiles in monocrotaline (MCT)- mice.

MATERIALS AND METHODS

Lung tissues (Control-Vehicle, MCT-Vehicle, and MCT-C75) were examined by high-throughput sequencing (HTS). Aberrantly expressed mRNAs and lncRNAs were analyzed by bioinformatics. Cell proliferation and cell cycle analysis were performed to detect the potential protective effects of C75, an inhibitor of fatty acid synthase. The signaling pathways associated with inflammatory responses were verified by real time-PCR.

RESULTS

RNA sequencing data reveals 285 differentially expressed genes (DEGs) and 147 lncRNAs in the MCT-Vehicle group compared to the control. After five-week of C75 treatment, 514 DEGs and 84 lncRNAs are aberrant compared to the MCT-Vehicle group. Analysis of DEGs and lncRNA target genes reveals that they were enriched in pathways related to cell cycle, cell division, and vascular smooth muscle contraction that contributes to the PAH pathological process. Subsequently, the expression of eight DEGs and three lncRNAs is verified using RT-PCR. Differentially expressed lncRNAs (ENSMUSG00000110393.2, Gm38850, ENSMUSG00000100465.1, ENSMUSG00000110399.1) may associate in PAH pathogenesis as suggested by co-expression network analysis. C75 can protect against MCT-induced PAH through its anti-inflammatory and anti-proliferation.

CONCLUSIONS

These DEGs and lncRNAs can be considered as novel candidate regulators of PAH pathogenesis. We propose that C75 treatment can partially reverse PAH pathogenesis through modulating cell cycle, cell proliferation, and anti-inflammatory.

Remodeling of imbalanced extracellular matrix homeostasis for reversal of pancreatic fibrosis

Pancreatic fibrosis is mainly manifested by imbalance in extracellular matrix (ECM) homeostasis due to excessive deposition of collagen in pancreas by activated pancreatic stellate cells (PSCs). Recently, some drugs have exhibited therapeutic potentials for the treatment of pancreatic fibrosis; however, currently, no effective clinical strategy is available to remodel imbalanced ECM homeostasis because of inferior targeting abilities of drugs and collagen barriers that hinder the efficient delivery of drugs. Herein, we design and prepare collagen-binding peptide (CBP) and collagenase I co-decorated dual drug-loaded lipid nanoparticles (named AT-CC) for pancreatic fibrosis therapy. Specifically, AT-CC can target fibrotic pancreas via the CBP and degrade excess collagen by the grafted collagenase I, thereby effectively delivering all-trans-retinoic acid (ATRA) and ammonium tetrathiomolybdate (TM) into pancreas. The released ATRA can reduce collagen overproduction by inhibiting the activation of PSCs. Moreover, the released TM can restrain lysyloxidase activation, consequently reducing collagen cross-linking. The combination of ATRA and TM represses collagen synthesis and reduces collagen cross linkages to restore ECM homeostasis. The results of this research suggest that AT-CC is a safe and efficient collagen-targeted degradation drug-delivery system for reversing pancreatic fibrosis. Furthermore, the strategy proposed herein will offer an innovative platform for the treatment of chronic pancreatitis.

CGRP induces myofibroblast differentiation and the production of extracellular matrix in MRC5s via autocrine and paracrine signalings

There are contradictory views on which calcitonin gene-related peptide (CGRP) causes pulmonary fibrosis. Fibrotic potency of CGRP was tested and compared to that of transforming growth factor-β (TGF-β). Myofibroblast differentiation, cell proliferation, and activations of TGF-β and Wnt pathways were examined for 24, 48, and 72 h in A549 and MRC5 cell lines stimulated with CGRP and TGF-β. CGRP-induced cell proliferation in MRC5s early on while cell proliferation in A549 occurred progressively. CGRP promoted fibroblast-myofibroblast differentiation by inducing the transcription of ACTA2, COL1A1, SMAD2/3, and SMAD4 genes, the production of collagen, fibronectin, α-smooth muscle actin, and activation of TGF-β signaling starting from 24 h. Additionally, TGF-β signaling induced by CGRP decreased the DKK1 level and activated the Wnt signaling in MRC5s. After CGRP stimulation, Wnt7a levels were increased from 24 to 72 h, while Wnt5a levels were elevated at 72 h in MRC5s. CGRP did not induce epithelial-mesenchymal transition in A549s, unlike TGF-β. A comparison of fibrotic potency of CGRP and TGF-β showed that TGF-β is a powerful profibrotic molecule and induces earlier myofibroblast differentiation. Even so, CGRP promotes myofibroblast differentiation and extracellular matrix production by inducing Smad-dependent-TGF-β and Wnt signalings via autocrine and paracrine signalings in MRC5s.

Copper chelation therapy inhibits renal fibrosis by modulating copper transport proteins

The copper (Cu) transporter proteins play an important role in the maintenance of the Cu homeostasis in the body. Lysyl oxidase (LOX) proteins are involved in crosslinking of collagens and elastin molecules resulting in the establishment of extracellular matrix (ECM) and require Cu for their functional activity. Although there are few reports showing the protective effects of Cu chelators, the mechanism behind protection remains unknown. The present study investigated the role of Cu transporter proteins in renal fibrosis. We used tubular epithelial cells and three different animal models of renal injury to investigate the induction of Cu transporter proteins in renal injury with different etiology. We used disulfiram, clioquinol as two Cu chelators and ammonium tetrathiomolybdate as a standard Cu chelator. In addition, β-aminopropionitrile (BAPN) was used as a standard LOX inhibitor. We demonstrated that renal fibrosis is associated with the induction of Cu transporter proteins such as ATP7A and Copper Transporter 1 (CTR1) but the Cu overload did not induce renal fibrosis. In addition, the Cu chelators inhibited renal fibrosis by inhibiting the Cu transporter proteins.

Atorvastatin attenuates pulmonary fibrosis in mice and human lung fibroblasts, by the regulation of myofibroblast differentiation and apoptosis

Statins have anti-inflammatory and antifibrotic effects in addition to cholesterol-lowering effect. We aimed to investigate the effect of atorvastatin (ATR) in fibrotic mouse lung and human lung fibroblasts (MRC5s). Pulmonary fibrosis was induced by a single dose of bleomycin by intratracheal instillation in adult mice. ATR was administered (20 mg/kg ip) to mice with healthy and pulmonary fibrosis for 10 days from Day 7 of the experiment. Mice were dissected on the 21st day. The levels of alpha-smooth muscle actin (α-SMA), pSMAD2/3, LOXL2, and p-Src were determined by Western blot analysis in the lungs. Furthermore, a group of MRC5 was differentiated into myofibroblasts by transforming growth factor-beta (TGF-β). Another group of MRC5s was treated with 10 µM ATR at 24 h after TGF-β stimulation. Cells were collected at 0, 24, 48, and 72 h. The effects of ATR on myofibroblast differentiation, apoptosis, and TGF-β and Wnt/β-catenin signaling activations were examined by Western blot analysis and flow cytometry in MRC5s. ATR attenuated pulmonary fibrosis by regulating myofibroblast differentiation and interstitial accumulation of collagen, by acting on LOXL2, p-Src, and pSMAD2/3 in mice lungs. Additionally, it blocked myofibroblast differentiation via reduced TGF-β and Wnt/β-catenin signaling and decreased α-SMA in MRC5s stimulated with TGF-β. Moreover, ATR caused myofibroblast apoptosis via caspase-3 activation. ATR treatment attenuates pulmonary fibrosis in mice treated with bleomycin. It also inhibits fibroblast/myofibroblast activation, by both reducing myofibroblasts differentiation and inducing myofibroblast apoptosis.

Tetrathiomolybdate Treatment Attenuates Bleomycin-Induced Angiogenesis and Lung Pathology in a Sheep Model of Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive chronic lung disease characterized by excessive extracellular matrix (ECM) deposition in the parenchyma of the lung. Accompanying the fibrotic remodeling, dysregulated angiogenesis has been observed and implicated in the development and progression of pulmonary fibrosis. Copper is known to be required for key processes involved in fibrosis and angiogenesis. We therefore hypothesized that lowering bioavailable serum copper with tetrathiomolybdate could be of therapeutic value for treating pulmonary fibrosis. This study aimed to investigate the effect of tetrathiomolybdate on angiogenesis and fibrosis induced in sheep lung segments infused with bleomycin. Twenty sheep received two fortnightly infusions of either bleomycin (3U), or saline (control) into two spatially separate lung segments. A week after the final bleomycin/saline infusions, sheep were randomly assigned into two groups (n = 10 per group) and received twice-weekly intravenous administrations of either 50 mg tetrathiomolybdate, or sterile saline (vehicle control), for 6 weeks. Vascular density, expressed as the percentage of capillary area to the total area of parenchyma, was determined in lung tissue sections immuno-stained with antibodies against CD34 and collagen type IV. The degree of fibrosis was assessed by histopathology scoring of H&E stained sections and collagen content using Masson's trichrome staining. Lung compliance was measured via a wedged bronchoscope procedure prior to and 7 weeks following final bleomycin infusion. In this large animal model, we show that copper lowering by tetrathiomolybdate chelation attenuates both bleomycin-induced angiogenesis and pulmonary fibrosis. Moreover, tetrathiomolybdate treatment downregulates vascular endothelial growth factor (VEGF) expression, and improved lung function in bleomycin-induced pulmonary fibrosis. Tetrathiomolybdate also suppressed the accumulation of inflammatory cells in bronchoalveolar lavage fluid 2 weeks after bleomycin injury. The molecular mechanism(s) underpinning copper modulation of fibrotic pathways is an important area for future investigation, and it represents a potential therapeutic target for pulmonary fibrosis.

Systemic sclerosis biomarkers detection in the secretome of TGFβ1-activated primary human lung fibroblasts

TGFβ1 is a profibrotic mediator that contributes to a broad spectrum of pathologies, including systemic sclerosis-associated pulmonary fibrosis (SSc-PF). However, the secretome of TGFβ1-stimulated primary human normal lung (NL) fibroblasts has not been well characterized. Using fluorescent 2-dimensional gel electrophoresis (2D-PAGE) and differential gel electrophoresis (DIGE) followed by Mass Spectrometry, we identified 37 differentially secreted proteins in the conditioned media of TGFβ1-activated NL fibroblasts and generated a protein-protein association network of the TGFβ1 secretome using STRING. Functional enrichment revealed that several biological processes and pathways characteristic of PF were enriched. Additionally, by comparing the TGFβ1 secretome of NL fibroblasts to proteomic biomarkers from biological fluids of systemic sclerosis (SSc) patients, we identified 11 overlapping proteins. Together our data validate the TGFβ1-induced secretome of NL fibroblasts as a valid in vitro model that reflects SSc biomarkers and identify potential therapeutic targets for SSc-PF. SIGNIFICANCE: All proteins secreted by fibroblasts into the extracellular space, representing the secretome, promote cell-to-cell communication as well as tissue homeostasis, immune mechanisms, developmental regulation, proteolysis, development of the extracellular matrix (ECM) and cell adhesion. Therefore, it is crucial to understand how TGFβ1, a well-known profibrotic cytokine, modulates the secretome of pulmonary fibroblasts, and how the TGFβ1-induced secretome resembles biomarkers in SSc. Using functional enrichment analysis, key pathways and hub proteins can be identified and studied as potential therapeutic targets for pulmonary fibrosis.

Targeting Lysyl Oxidase Family Meditated Matrix Cross-Linking as an Anti-Stromal Therapy in Solid Tumours

Simple Summary

To improve efficacy of solid cancer treatment, efforts have shifted towards targeting both the cancer cells and the surrounding tumour tissue they grow in. The lysyl oxidase (LOX) family of enzymes underpin the fibrotic remodeling of the tumour microenvironment to promote both cancer growth, spread throughout the body and modulate response to therapies. This review examines how the lysyl oxidase family is involved in tumour development, how they can be targeted, and their potential as diagnostic and prognostic biomarkers in solid tumours.

Abstract

The lysyl oxidase (LOX) family of enzymes are a major driver in the biogenesis of desmoplastic matrix at the primary tumour and secondary metastatic sites. With the increasing interest in and development of anti-stromal therapies aimed at improving clinical outcomes of cancer patients, the Lox family has emerged as a potentially powerful clinical target. This review examines how lysyl oxidase family dysregulation in solid cancers contributes to disease progression and poor patient outcomes, as well as an evaluation of the preclinical landscape of LOX family targeting therapeutics. We also discuss the suitability of the LOX family as a diagnostic and/or prognostic marker in solid tumours.

Inhibition of ROS/NLRP3/Caspase-1 mediated pyroptosis alleviates excess molybdenum-induced apoptosis in duck renal tubular epithelial cells

OBJECTIVE

Excess molybdenum (Mo) is harmful to the body, and the kidney is the vital target organ for Mo exposure. This study focused on the impacts of excess Mo on pyroptosis and the relationship between pyroptosis and apoptosis in kidney.

METHODS

The duck renal tubular epithelial cells were treated with (NH₄)₆Mo₇O₂₄·4H₂O (0, 480, 720 and 960 μM Mo), N-acetyl-L-cysteine (NAC) (100 μM), Z-YVAD-fluoromethylketone (YVAD) (10 μM) and the combination of Mo and NAC or YVAD for 12 h. The LDH release and IL-1β, IL-18 contents of cell supernatant were detected by LDH and ELISA kits. The MMP and ROS level were measured using MMP and ROS kits by flow cytometry. The apoptotic rate of cell was detected by AO/EB counterstaining. Pyroptosis and apoptosis-related factors mRNA and protein levels were assayed by real-time qPCR and western blot, respectively.

RESULTS

Excessive Mo markedly increased LDH, IL-18, IL-1β releases and induced overproduction of ROS, pyroptosis-related factors mRNA and protein levels. NAC and YVAD dramatically decreased pyroptosis induced by Mo. Simultaneously, YVAD significantly changed apoptosis-related factors mRNA and protein levels, and reduced cell apoptotic rate.

CONCLUSION

Excessive Mo exposure can induce pyroptosis by the ROS/NLRP3/Caspase-1 pathway in duck renal tubular epithelial cells, and restraining pyroptosis of Caspase-1 dependence might weaken excess Mo-induced apoptosis. The study provides theoretical basis for excess Mo exposure nephrotoxic researches on waterfowl and the interplay between pyroptosis and apoptosis highlights a new sight into the mechanism of Mo-induced nephrotoxicity.

Genetic Susceptibility and Protein Expression of Extracellular Matrix Turnover-Related Genes in Oral Submucous Fibrosis

Betel quid (BQ) chewing increased the risk of oral cancer and oral submucous fibrosis (OSMF), an oral premalignant disorder (OPMD) with malignant transformation potential. BQ components such as areca nut (AN), trauma by coarse AN fiber, catechin, copper, alkaloids, stimulated reactive oxygen species (ROS), inflammation and cytotoxicity are suggested to be the contributing factors. They may induce tissue inflammation, proliferation of fibroblasts and collagen deposition, myofibroblast differentiation and contraction, collagen cross-links and inhibit collagen phagocytosis, finally leading to the development of OSMF and oral cancer. These events are mediated by BQ components-induced changes of extracellular matrix (ECM) turnover via regulation of TGF-β1, plasminogen activator inhibitor-1 (PAI-1), cystatin, lysyl oxidase (LOX) and tissue inhibitors of metalloproteinases (TIMPs) and metalloproteinases (MMPs). Genetic susceptibility is also involved in these disease processes. Further understanding the molecular mechanisms of BQ-induced OSMF and oral cancer can be helpful for future disease prevention and treatment.

Insights into the Role of Bioactive Food Ingredients and the Microbiome in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic disease mainly associated with aging and, to date, its causes are still largely unknown. It has been shown that dietary habits can accelerate or delay the occurrence of aging-related diseases; however, their potential role in IPF development has been underestimated so far. The present review summarizes the evidence regarding the relationship between diet and IPF in humans, and in animal models of pulmonary fibrosis, in which we discuss the bioactivity of specific dietary food ingredients, including fatty acids, peptides, amino acids, carbohydrates, vitamins, minerals and phytochemicals. Interestingly, many animal studies reveal preventive and therapeutic effects of particular compounds. Furthermore, it has been recently suggested that the lung and gut microbiota could be involved in IPF, a relationship which may be linked to changes in immunological and inflammatory factors. Thus, all the evidence so far puts forward the idea that the gut-lung axis could be modulated by dietary factors, which in turn have an influence on IPF development. Overall, the data reviewed here support the notion of identifying food ingredients with potential benefits in IPF, with the ultimate aim of designing nutritional approaches as an adjuvant therapeutic strategy.

Lysyl Oxidase (LOX) Family Members: Rationale and Their Potential as Therapeutic Targets for Liver Fibrosis

The cross-linking of structural extracellular matrix (ECM) components, especially fibrillar collagens and elastin, is strongly implicated in fibrosis progression and resistance to fibrosis reversal. Lysyl oxidase family members (LOX and LOXL1 [lysyl oxidase-like 1], LOXL2 [lysyl oxidase-like 2], LOXL3 [lysyl oxidase-like 3], and LOXL4 [lysyl oxidase like 4]) are extracellular copper-dependent enzymes that play a key role in ECM cross-linking, but have also other intracellular functions relevant to fibrosis and carcinogenesis. Although the expression of most LOX family members is elevated in experimental liver fibrosis of diverse etiologies, their individual contribution to fibrosis is incompletely understood. Inhibition of the LOX family as a whole and of LOX, LOXL1, and LOXL2 specifically has been shown to suppress fibrosis progression and accelerate its reversal in rodent models of cardiac, renal, pulmonary, and liver fibrosis. Recent disappointing clinical trials with a monoclonal antibody against LOXL2 (simtuzumab) in patients with pulmonary and liver fibrosis dampened enthusiasm for LOX family member inhibition. However, this unexpected negative outcome may be related to the inefficient antibody, rather than to LOXL2, not qualifying as a relevant antifibrotic target. Moreover, LOX family members other than LOXL2 may prove to be attractive therapeutic targets. In this review, we summarize the structural hallmarks, expression patterns, covalent cross-linking activities, and modes of regulation of LOX family members and discuss the clinical potential of their inhibition to treat fibrosis in general and liver fibrosis in particular.

Role of the lysyl oxidase enzyme family in cardiac function and disease

Heart diseases are a major cause of morbidity and mortality world-wide. Lysyl oxidase (LOX) and related LOX-like (LOXL) isoforms play a vital role in remodelling the extracellular matrix (ECM). The LOX family controls ECM formation by cross-linking collagen and elastin chains. LOX/LOXL proteins are copper-dependent amine oxidases that catalyse the oxidation of lysine, causing cross-linking between the lysine moieties of lysine-rich proteins. Dynamic changes in LOX and LOXL protein-expression occur in a variety of cardiac pathologies; these changes are believed to be central to the associated tissue-fibrosis. An awareness of the potential pathophysiological importance of LOX has led to the evaluation of interventions that target LOX/LOXL proteins for heart-disease therapy. The purposes of this review article are: (i) to summarize the basic biochemistry and enzyme function of LOX and LOXL proteins; (ii) to consider their tissue and species distribution; and (iii) to review the results of experimental studies of the roles of LOX and LOXL proteins in heart disease, addressing involvement in the mechanisms, pathophysiology and therapeutic responses based on observations in patient samples and relevant animal models. Therapeutic targeting of LOX family enzymes has shown promising results in animal models, but small-molecule approaches have been limited by non-specificity and off-target effects. Biological approaches show potential promise but are in their infancy. While there is strong evidence for LOX-family protein participation in heart failure, myocardial infarction, cardiac hypertrophy, dilated cardiomyopathy, atrial fibrillation and hypertension, as well as potential interest as therapeutic targets, the precise involvement of LOX-family proteins in heart disease requires further investigation.

Gastrin-releasing peptide induces fibrotic response in MRC5s and proliferation in A549s

Idiopathic pulmonary fibrosis (IPF) is a complex lung disease, whose build-up scar tissue is induced by several molecules. Gastrin-releasing peptide (GRP) is released from pulmonary neuroendocrine cells, alveolar macrophages, and some nerve endings in the lung. A possible role of GRP in IPF is unclear. We aimed to investigate the fibrotic response to GRP, at the cellular level in MRC5 and A549 cell lines. The proliferative and fibrotic effects of GRP on these cells were evaluated by using BrdU, immunoblotting, immunofluorescence and qRT-PCR for molecules associated with myofibroblast differentiation, TGF-β and Wnt signalling. All doses of GRP increased the amount of BrdU incorporation in A549 cells. In contrast, the amount of BrdU increased in MRC5 cells in the first 24 h, though progressively decreased by 72 h. GRP did not stimulate epithelial-mesenchymal transition in A549 cells, rather, it stimulated the differentiation of MRC5 cells into myofibroblasts. Furthermore, GRP induced gene and protein expressions of p-Smad2/3 and Smad4, and reduced the levels of Smad7 in MRC5 cells. In addition, GRP decreased Wnt5a protein levels and stimulated β-catenin activation by increasing Wnt4, Wnt7a and β-catenin protein levels. GRP caused myofibroblast differentiation by inducing TGF-βand Wnt pathways via paracrine and autocrine signalling in MRC5 cells. In conclusion, GRP may lead to pulmonary fibrosis due to its proliferative and fibrotic effects on lung fibroblasts. The abrogation of GRP-mediated signal activation might be considered as a treatment modality for fibrotic lung diseases. Video Abstract.

Control of the Lung Residence Time of Highly Permeable Molecules after Nebulization: Example of the Fluoroquinolones

Pulmonary drug delivery is a promising strategy to treat lung infectious disease as it allows for a high local drug concentration and low systemic side effects. This is particularly true for low-permeability drugs, such as tobramycin or colistin, that penetrate the lung at a low rate after systemic administration and greatly benefit from lung administration in terms of the local drug concentration. However, for relatively high-permeable drugs, such as fluoroquinolones (FQs), the rate of absorption is so high that the pulmonary administration has no therapeutic advantage compared to systemic or oral administration. Formulation strategies have thus been developed to decrease the absorption rate and increase FQs’ residence time in the lung after inhalation. In the present review, some of these strategies, which generally consist of either decreasing the lung epithelium permeability or decreasing the release rate of FQs into the epithelial lining fluid after lung deposition, are presented in regards to their clinical aspects.

Current Biomedical Use of Copper Chelation Therapy

Copper is an essential microelement that plays an important role in a wide variety of biological processes. Copper concentration has to be finely regulated, as any imbalance in its homeostasis can induce abnormalities. In particular, excess copper plays an important role in the etiopathogenesis of the genetic disease Wilson's syndrome, in neurological and neurodegenerative pathologies such as Alzheimer's and Parkinson's diseases, in idiopathic pulmonary fibrosis, in diabetes, and in several forms of cancer. Copper chelating agents are among the most promising tools to keep copper concentration at physiological levels. In this review, we focus on the most relevant compounds experimentally and clinically evaluated for their ability to counteract copper homeostasis deregulation. In particular, we provide a general overview of the main disorders characterized by a pathological increase in copper levels, summarizing the principal copper chelating therapies adopted in clinical trials.

Copper-Heparin Inhalation Therapy To Repair Emphysema: A Scientific Rationale

Current pharmacotherapy of chronic obstructive pulmonary disease (COPD) aims at reducing respiratory symptoms and exacerbation frequency. Effective therapies to reduce disease progression, however, are still lacking. Furthermore, COPD medications showed less favorable effects in emphysema than in other COPD phenotypes. Elastin fibers are reduced and disrupted, whereas collagen levels are increased in emphysematous lungs. Protease/antiprotease imbalance has historically been regarded as the sole cause of emphysema. However, it is nowadays appreciated that emphysema may also be provoked by perturbations in the sequential repair steps following elastolysis. Essentiality of fibulin-5 and lysyl oxidase-like 1 in the elastin restoration process is discussed, and it is argued that copper deficiency is a plausible reason for failing elastin repair in emphysema patients. Since copper-dependent lysyl oxidases crosslink elastin as well as collagen fibers, copper supplementation stimulates accumulation of both proteins in the extracellular matrix. Restoration of abnormal elastin fibers in emphysematous lungs is favorable, whereas stimulating pulmonary fibrosis formation by further increasing collagen concentrations and organization is detrimental. Heparin inhibits collagen crosslinking while stimulating elastin repair and might therefore be the ideal companion of copper for emphysema patients. Efficacy and safety considerations may lead to a preference of pulmonary administration of copper-heparin over systemic administration.

The effects of atorvastatin on the kidney injury in mice with pulmonary fibrosis

OBJECTIVES

The present study investigated the effects of atorvastatin on kidney injury in mice with pulmonary fibrosis (PF).

METHODS

Adult mice were divided into four groups: mice treated with intratracheal bleomycin (I) and their controls (II), and mice treated with atorvastatin for 10 days after 7 days from bleomycin treatment (III) and their controls (IV). Mice were dissected on the 21st day.

KEY FINDINGS

Mononuclear cell infiltrations, injured proximal tubule epithelium and p-c-Jun level increased, while cell proliferation and the levels of p-SMAD2, ELK1, p-ELK1, p-ATF2 and c-Jun decreased in the kidney tissue of mice with PF. The atorvastatin treatments to mice with PF resulted in significant increases at the TGF-β activation, cell proliferation and kidney damage and decreases in the levels of p-SMAD2, p-ELK1, p-ATF2 and p-c-Jun, but not change the p-SMAD3, ELK1 and ATF2 in kidneys.

CONCLUSIONS

The depletion of MAPK signals, rather than SMAD signalling, is effective in kidney damage of mice with PF. Atorvastatin did not regress kidney damage in these mice, whereas it increases the kidney injury. The c-Jun-mediated JNK signals could help kidney repair through cell proliferation. The treatment time and doses of atorvastatin should be optimized for regression of kidney damage.

LOX/LOXL in pulmonary fibrosis: potential therapeutic targets

Lysyl oxidase (LOX) and lysyl oxidase-like proteins (LOXL), a family of extracellular matrix (ECM) crosslinking enzymes that have been recognised as playing an important role in fibrogenesis for more than 40 years, are logical targets for antifibrotic treatments. Pulmonary fibrosis, especially idiopathic pulmonary fibrosis (IPF), is a progressive and lethal disease characterised by excessive deposition of ECM in the lung parenchyma. In this review, we discuss the current clinical approaches for IPF and review members of LOX family-LOX, LOXL1, LOXL2, LOXL3 and LOXL4 in IPF patients and in animal models of bleomycin-induced pulmonary fibrosis. Although these findings are controversial and require further validation, LOX/LOXL1/LOXL2 as potential therapeutic targets for IPF deserve continued attention. So far to our knowledge, LOXL3 or LOXL4 has not clearly shown specific therapeutic potential.

Exendin-4 partly ameliorates - hyperglycemia-mediated tissue damage in lungs of streptozotocin-induced diabetic mice

Glucagon-like peptide-1 (GLP-1) stimulates insulin secretion, - plays anti-inflammatory role in atherosclerosis, and has surfactant-releasing effects in lungs. GLP-1 analogues are used in diabetes therapy. This is the first study to investigate the effects of exendin-4, a GLP-1 receptor agonist, on lung injury in diabetic mice. BALB/c male mice were divided into four groups. The first group was given only citrate buffer, the second group was given only exendin-4, the third group was given only streptozotocin (STZ), and the fourth group was given both exendin-4 and STZ. Exendin-4 (3μg/kg) was administered daily by subcutaneous injection for 30days after mice were rendered diabetic with a single dose of STZ (200mg/kg). Structural alterations, oxidative stress, apoptosis, insulin signaling and expressions of prosurfactant-C, alpha-smooth muscle actin, collagen-I and fibronectin were evaluated in lung tissue. Diabetic mice lungs were characterized by induced oxidative stress, apoptosis, edema, and cell proliferation. They had honeycomb-like alveoli, thicker alveolar walls, and hypertrophic pneumocytes. Although exendin-4 treatment improved pulmonary edema, apoptosis, oxidative stress, and lung injury, it led to the disrupted insulin signaling and interstitial collagen accumulation in the lungs of diabetic mice. Exendin-4 ameliorates hyperglycemia-mediated lung damage by reducing glucose, -oxidative stress and stimulating cell proliferation. However, exendin-4 led to increased lung injury partly by reducing insulin signaling - and collagen accumulation around pulmonary vasculature in diabetic mice.

The copper dependent-lysyl oxidases contribute to the pathogenesis of pulmonary emphysema in chronic obstructive pulmonary disease patients

Abnormalities in the elastic fiber biology are seen in pulmonary emphysema (PE). The copper-dependent lysyl oxidases regulate the production and accumulation of elastic fibers in the connective tissue. This study focused on the relationship between lysyl oxidase (LOX), LOX-like protein 1 (LOXL1), and LOXL2 and PE pathogenesis. Lung samples with or without PE from patients with chronic obstructive lung disease (n=35) were used. Protein levels of elastin, LOX, LOXL1, LOXL2, hypoxia inducible factor 1-alpha (HIF-1α), copper metabolism domain containing-1 (COMMD1), and phosphatase and tensin homolog (PTEN) were assayed using microscopic and biochemical methods The emphysematous areas were characterized by enlargement of the alveoli, destruction of the alveolar structure, accumulation of macrophages in the alveolar lumens, and showed increased HIF-1α immunoreactivity. Additionally, the emphysematous areas had significantly lower elastin, LOX, LOXL1, LOXL2, HIF-1α, COMMD1, and PTEN protein levels than the non-emphysematous areas. We suppose that the reductions in the HIF-1α levels led to decreases in the protein levels of active LOX, LOXL1, and LOXL2. These decreases might cause abnormalities in the elastic fiber biology. HIF-1α activation induced by decreased COMMD1 and protease activation induced by decreased PTEN might contribute to the development of PE. Finally, methods aimed at increasing the protein levels of LOXs, COMMD1 and PTEN might be effective for treating PE.

Lysyl oxidase isoforms in gastric cancer

Gastric cancer (GC) is the fifth most frequent cancer in the world and shows the highest incidence in Latin America and Asia. An increasing amount of evidence demonstrates that lysyl oxidase isoforms, a group of extracellular matrix crosslinking enzymes, should be considered as potential biomarkers and therapeutic targets in GC. In this review, we focus on the expression levels of lysyl oxidase isoforms, its functions and the clinical implications in GC. Finding novel proteins related to the processing of these extracellular matrix enzymes might be helpful in the design of new therapies, which, in combination with classic pharmacology, could be used to delay the progress of this aggressive cancer and offer a wider temporal window for clinical intervention.

Decreased copper concentrations but increased lysyl oxidase activity in ischemic hearts of rhesus monkeys

Myocardial ischemia leads to a decrease in copper (Cu) concentrations, along with collagen deposition in which Cu-dependent lysyl oxidase (LOX) catalyzes the cross-linking of collagens leading to tissue stiffness. The present study was undertaken to determine the relationship between decreased Cu concentrations and LOX activities in ischemic hearts of monkeys. Rhesus monkeys were subjected to coronary artery ligation, leading to ischemic infarction. At 8 weeks after the surgery, Cu concentrations and Cu-dependent cytochrome c oxidase (CCO) activities in the infarct area were significantly decreased. Unexpectedly, the Cu-dependent LOX activities in the same area were significantly increased. LOX proteins were accumulated in the cytosol of myofibroblasts, endothelial cells, and residual cardiomyocytes in the infarct area. In contrast, LOX was only found in fibroblasts and myocardial intercalated discs between cardiomyocytes in sham-operated controls. The LOX mRNA level was also increased in the infarct area compared to the sham operated control. This upregulation of LOX was associated with significant increases in collagen deposition; protein levels of type I and III collagens were significantly increased along with increases in their mRNA levels in the infarct area. This finding indicates that under myocardial infarction, Cu-dependent CCO activities were depressed but LOX activities were increased most likely through Cu redistribution although Cu concentrations were significantly depressed.

Lysyl Oxidase Isoforms and Potential Therapeutic Opportunities for Fibrosis and Cancer

INTRODUCTION

The lysyl oxidase family of enzymes is classically known as being required for connective tissue maturation by oxidizing lysine residues in elastin and lysine and hydroxylysine residues in collagen precursors. The resulting aldehydes then participate in cross-link formation, which is required for normal connective tissue integrity. These enzymes have biological functions that extend beyond this fundamental biosynthetic role, with contributions to angiogenesis, cell proliferation, and cell differentiation. Dysregulation of lysyl oxidases occurs in multiple pathologies including fibrosis, primary and metastatic cancers, and complications of diabetes in a variety of tissues.

AREAS COVERED

This review summarizes the major findings of novel roles for lysyl oxidases in pathologies, and highlights some of the potential therapeutic approaches that are in development and which stem from these new findings.

EXPERT OPINION

Fundamental questions remain regarding the mechanisms of novel biological functions of this family of proteins, and regarding functions that are independent of their catalytic enzyme activity. However, progress is underway in the development of isoform-specific pharmacologic inhibitors, potential therapeutic antibodies and gaining an increased understanding of both tumor suppressor and metastasis promotion activities. Ultimately, this is likely to lead to novel therapeutic agents.

Personalized medicine in idiopathic pulmonary fibrosis: facts and promises

PURPOSE OF REVIEW

In this article, we summarize and discuss the most recent literature on personalized medicine in idiopathic pulmonary fibrosis (IPF), a chronic progressive and almost invariably lethal disease of unknown cause. This review is timely as major advances in our understanding of disease pathobiology and improvements in molecular techniques have recently led to the identification of potential surrogates of diagnosis, prognosis and response to treatment.

RECENT FINDINGS

The most promising and advanced candidate biomarkers are presented based on their proposed mechanistic pathways (e.g. alveolar epithelial cell dysfunction, immune dysregulation, microbiome, extracellular matrix remodeling and fibroproliferation, epigenetic markers and metabolomics). Recent data suggest that components of the immune system may contribute to the development of IPF. A potential role for infections as a cofactor in disease development and progression or as a trigger in disease exacerbation has also recently been proposed.

SUMMARY

Clinical management of IPF is unsatisfactory because of limited availability of truly effective therapies, lack of accurate predictors of disease behavior and absence of simple short-term measures of therapeutic response. A number of putative biomarkers have been identified in patients with IPF, although none has been validated to the standard necessary for their use in either therapeutic trials or clinical practice. Currently, ongoing prospective longitudinal studies will hopefully permit such validation.

Dasatinib attenuated bleomycin-induced pulmonary fibrosis in mice

Anti-fibrotic effect of dasatinib, a platelet-derived growth factor receptor (PDGFR) and Src-kinase inhibitor, was tested on pulmonary fibrosis (PF). Adult mice were divided into four groups: mice dissected 21 d after the bleomycin (BLM) instillation (0.08 mg/kg in 200 µl) (I) and their controls (II), and mice treated with dasatinib (8 mg/kg in 100 µl, gavage) for one week 14 d after BLM instillation and dissected 21 d after instillation (III) and their controls (IV). The fibrosis score and the levels of fibrotic markers were analyzed in lungs. BLM treatment-induced cell proliferation and increased the levels of collagen-1, alpha smooth muscle actin, phospho (p)-PDGFR-alpha, p-Src, p-extracellular signal-regulated kinases1/2 and p-cytoplasmic-Abelson-kinase (c-Abl) in lungs, and down-regulated PTEN expression. Dasatinib reversed these alterations in the fibrotic lung. Dasatinib limited myofibroblast activation and collagen-1 accumulation by the inhibition of PDGFR-alpha, and Src and c-Abl activations. In conclusion, dasatinib may be a novel tyrosine and Src-kinase inhibitor for PF regression in mice.