Activation Of Profibrotic Pathways Research Articles

Glomerular Elasticity and Gene Expression Patterns Define Two Phases of Alport Nephropathy.

Early steps in glomerular injury are poorly understood in collagen IV nephropathies. We characterized structural, functional, and biophysical properties of glomerular capillaries and podocytes in Col4α3-/- mice and analyzed kidney cortex transcriptional profiles at various disease stages. We investigated the effects of TUDCA (suppresses ER stress) on these parameters and used human FSGS transcriptomic data to identify pathways rescued by TUDCA. In Col4α3-/- mice, podocyte injury develops by 3 months, with maximum glomerular deformability and 40% podocyte loss at 4 months. This period is followed is followed by glomerular capillary stiffening, proteinuria, reduced renal function, inflammatory infiltrates, and fibrosis. Bulk RNA sequencing at sequential time points revealed progressive increases in inflammatory and injury gene expression, and activation of the TNF pathway. Mapping Podocyte-enriched genes from FSGS patients to mice showed that TUDCA, which mitigated renal injury suppressed molecular pathways associated with podocyte stress, hypertrophy and tubulo-interstitial injury. Col4α3-/- nephropathy progresses in two phases. The first is characterized by podocytopathy, increased glomerular capillary deformability and accelerated podocyte loss, and the second by increased capillary wall stiffening and renal inflammatory and profibrotic pathway activation. The response of podocytes to TUDCA treatment provides insights into signaling pathways in Alport and related nephropathies.

Phenotypic Spectrum of Subclinical Sarcomere-Related Hypertrophic Cardiomyopathy and Transition to Overt Disease.

Genetic hypertrophic cardiomyopathy (HCM) is classically caused by pathogenic/likely pathogenic variants in sarcomere genes (G+). Currently, HCM is diagnosed if there is unexplained left ventricular (LV) hypertrophy with LV wall thickness ≥15 mm in probands or ≥13 mm in at-risk relatives. Although LV hypertrophy is a key feature, this binary metric does not encompass the full constellation of phenotypic features, particularly in the subclinical stage of the disease. Subtle phenotypic manifestations can be identified in sarcomere variant carriers with normal LV wall thickness, before diagnosis with HCM (G+/LV hypertrophy-; subclinical HCM). We conducted a systematic review to summarize current knowledge about the phenotypic spectrum of subclinical HCM and factors influencing penetrance and expressivity. Although the mechanisms driving the development of LV hypertrophy are yet to be elucidated, activation of profibrotic pathways, impaired relaxation, abnormal Ca2+ signaling, altered myocardial energetics, and microvascular dysfunction have all been identified in subclinical HCM. Progression from subclinical to clinically overt HCM may be more likely if early phenotypic manifestations are present, including ECG abnormalities, longer mitral valve leaflets, lower global E' velocities on Doppler echocardiography, and higher serum N-terminal propeptide of B-type natriuretic peptide. Longitudinal studies of variant carriers are critically needed to improve our understanding of penetrance, characterize the transition to disease, identify risk predictors of phenotypic evolution, and guide the development of novel treatment strategies aimed at influencing disease trajectory.

Optimizing antidotal treatment with the oral HSP90 inhibitor TAS-116 against hydrochloric acid-induced pulmonary fibrosis in mice.

Exposure to high concentrations of hydrochloric acid (HCl) can lead to severe acute and chronic lung injury. In the aftermath of accidental spills, victims may be treated for the acute symptoms, but the chronic injury is often overlooked. We have developed a mouse model of acute and chronic lung injury, in which the peak of acute lung injury occurs on the day 4 after HCl exposure. We have also demonstrated that HSP90 inhibitors are effective antidotes when administered starting 24h after HCl. In this study we examined the hypothesis that the novel oral HSP90 inhibitor TAS-116 can effectively ameliorate HCl-induced lung injury even when treatment starts at the peak of the acute injury, as late as 96h after HCl. C57BI/6J mice were intratracheally instilled with 0.1N HCl. After 24 or 96h, TAS-116 treatment began (3.5, 7 or 14mg/kg, 5 times per week, p. o.) for either 2,3 or 4 orweeks. TAS-116 moderated the HCl-induced alveolar inflammation, as reflected in the reduction of white blood cells and total protein content in bronchoalveolar lavage fluid (BALF), overexpression of NLRP3 inflammasome, and inhibited the activation of pro-fibrotic pathways. Furthermore, TAS-116 normalized lung mechanics and decreased the deposition of extracellular matrix proteins in the lungs of mice exposed to HCl. Delayed and shortened treatment with TAS-116, successfully blocked the adverse chronic effects associated with acute exposure to HCl.

Pharmacological blockade of αV integrin (CD51) reduces the development of pressure-overload-induced cardiac fibrosis

Myocardial fibrosis is involved in most forms of heart diseases, progressively leading to adverse cardiac remodeling and heart failure. We previously identified a population of cardiac stromal cells that contribute to fibrosis development through a CD51 (alpha v integrin) dependent activation of pro-fibrotic pathways in a murine model of myocardial infarction. The pharmacological blockade of CD51 was associated with a significant reduction of fibrosis, preservation of cardiac function and improved survival. Investigate the impact of CD51 pharmacological blockers on the development of cardiac fibrosis induced by neurohormonal pro-hypertrophic stressors. We used C57Bl/6J mice infused with Angiotensin II (1.44 mg/kg/day) or dual Angiotensin II (1.44 mg/kg/day) + PhenylEphrine (50 mg/kg/day) through an osmotic pump for 28 or 14 days, respectively. Animals were treated with daily with intra-peritoneal injection of either CD51 blocker cilengitide or vehicle for the duration of the study. We found that both AngII and AngII + PE stimulation led to a similar cardiac hypertrophic remodeling: heart weight on body weight ratio as well as cardiomyocyte size were similarly increased. However, AngII + PE mice developed a significantly higher amount of interstitial fibrosis as compared to AngII mice (10.2 ± 4.3% vs. 4.5 ± 1.3% of total area respectively, P < 0.0001). Importantly, AngII + PE but not AngII mice exhibited a significant increase in CD51 expression and in the number of CD51+ cells as found in cytometry analysis. CD51 blockade significantly decreased the development of fibrosis under AngII + PE stimulation (7.6% ± 1.7, P < 0.05), as well as heart weight on body weight ratio (5.4 ± 0.5 vs. 5.7 ± 0.4, P < 0.05), but did not change the cardiomyocyte sizes. CD51 blockade also partially rescued the progressive drop in LVEF observed in mice stimulated with AngII + PE (47.5% ± 4.0 vs. 40.7% ± 13.8). Further cytometry analyses on cardiac tissues demonstrated that CD51 is expressed by stromal cells and by CCR2+ macrophages. Preliminary results indicate that the anti-fibrotic effects of CD51 blockade could come from a dual reduction on the activation of stromal and the immune-inflammatory response. Inhibition of CD51 reduces the development of cardiac fibrosis in response to pressure-overload, through the targeting of both stromal and inflammatory cardiac cells.

The Heat Shock Protein 90 Inhibitor, AT13387, Protects the Alveolo-Capillary Barrier and Prevents HCl-Induced Chronic Lung Injury and Pulmonary Fibrosis.

Hydrochloric acid (HCl) exposure causes asthma-like conditions, reactive airways dysfunction syndrome, and pulmonary fibrosis. Heat Shock Protein 90 (HSP90) is a molecular chaperone that regulates multiple cellular processes. HSP90 inhibitors are undergoing clinical trials for cancer and are also being studied in various pre-clinical settings for their anti-inflammatory and anti-fibrotic effects. Here we investigated the ability of the heat shock protein 90 (HSP90) inhibitor AT13387 to prevent chronic lung injury induced by exposure to HCl in vivo and its protective role in the endothelial barrier in vitro. We instilled C57Bl/6J mice with 0.1N HCl (2 µL/g body weight, intratracheally) and after 24 h began treatment with vehicle or AT13387 (10 or 15 mg/kg, SC), administered 3×/week; we analyzed histological, functional, and molecular markers 30 days after HCl. In addition, we monitored transendothelial electrical resistance (TER) and protein expression in a monolayer of human lung microvascular endothelial cells (HLMVEC) exposed to HCl (0.02 N) and treated with vehicle or AT13387 (2 µM). HCl provoked persistent alveolar inflammation; activation of profibrotic pathways (MAPK/ERK, HSP90); increased deposition of collagen, fibronectin and elastin; histological evidence of fibrosis; and a decline in lung function reflected in a downward shift in pressure–volume curves, increased respiratory system resistance (Rrs), elastance (Ers), tissue damping (G), and hyperresponsiveness to methacholine. Treatment with 15 mg/kg AT13387reduced alveolar inflammation, fibrosis, and NLRP3 staining; blocked activation of ERK and HSP90; and attenuated the deposition of collagen and the development of chronic lung injury and airway hyperreactivity. In vitro, AT13387 prevented HCl-induced loss of barrier function and AKT, ERK, and ROCK1 activation, and restored HSP70 and cofilin expression. The HSP90 inhibitor, AT13387, represents a promising drug candidate for chronic lung injury that can be administered subcutaneously in the field, and at low, non-toxic doses.

Expression of Fibrosis-Related Genes in Liver and Kidney Fibrosis in Comparison to Inflammatory Bowel Diseases.

Fibrosis is an important feature of inflammatory bowel diseases (IBD), but its pathogenesis is incompletely understood. Our aim was to identify genes important for fibrosis in IBD by comparison with kidney and liver fibrosis. First, we performed bioinformatics analysis of Gene Expression Omnibus datasets of liver and kidney fibrosis and identified CXCL9, THBS2, MGP, PTPRC, CD52, GZMA, DPT and DCN as potentially important genes with altered expression in fibrosis. We then performed qPCR analysis of the selected genes’ expression on samples of fibrotic kidney, liver, Crohn’s disease (CD) with and without fibrosis and ulcerative colitis (UC), in comparison to corresponding normal tissue. We found significantly altered expression in fibrosis for all selected genes. A significant difference for some genes was observed in CD with fibrosis in comparison to CD without fibrosis and UC. We conclude that similar changes in the expression of selected genes in liver, kidney fibrosis and IBD provide further evidence that fibrosis in IBD might share common mechanisms with other organs, supporting the hypothesis that fibrosis is the common pathway in diseases of various organs. Some genes were already active in IBD with inflammation without fibrosis, suggesting the early activation of profibrotic pathways or overlapping function in fibrosis and inflammation.

Molecular programs of fibrotic change in aging human lung

Lung fibrosis is increasingly detected with aging and has been associated with poor outcomes in acute lung injury or infection. However, the molecular programs driving this pro-fibrotic evolution are unclear. Here we profile distal lung samples from healthy human donors across the lifespan. Gene expression profiling by bulk RNAseq reveals both increasing cellular senescence and pro-fibrotic pathway activation with age. Quantitation of telomere length shows progressive shortening with age, which is associated with DNA damage foci and cellular senescence. Cell type deconvolution analysis of the RNAseq data indicates a progressive loss of lung epithelial cells and an increasing proportion of fibroblasts with age. Consistent with this pro-fibrotic profile, second harmonic imaging of aged lungs demonstrates increased density of interstitial collagen as well as decreased alveolar expansion and surfactant secretion. In this work, we reveal the transcriptional and structural features of fibrosis and associated functional impairment in normal lung aging.

Basigin genetic depletion reduces thoracic aortic aneurysm formation in marfan syndrome mice

Abstract Background Marfan Syndrome (MFS) is a rare genetic disease due to mutations in fibrillin 1 gene [1]. It is characterized by thoracic aortic aneurysm (TAA), whose dissection is the major cause of morbidity and mortality in MFS patients [2]. While pathological mechanisms underlying MFS extracellular matrix remodelling have started to be elucidated, an etiological treatment is not available yet [3,4]. Recently, EMMPRIN has been proposed as new actor in pro-fibrotic processes associated with TAA development in MFS patients [4,5]. Purpose To confirm the role of EMMPRIN (i.e. Basigin in mice, Bsg) in TAA formation and progression in a preclinical setting, we assessed whether Bsg genetic depletion in a mouse model of MFS (Fbn1C1039G/+) [6] had an impact on aortic phenotype. Methods We generated a double transgenic mouse model, Fbn1C1039G/+-Bsg+/−, by crossing commercially available Fbn1C1039G/+ with Bsg+/− mice (provided by Dr. Kadomatsu) [7] and we prospectively measured aortic root size in 12 Fbn1C1039G/+-Bsg+/−, 9 Fbn1C1039G/+, and 15 WT mice every 4 weeks from 12 to 20 weeks of age by 2D-echocardiography. Both qRT-PCR and Western Blot were used to evaluate EMMPRIN downstream pro-fibrotic pathway activation in thoracic aortic tissue obtained from mice sacrificed at 12 weeks. Plasma soluble EMMPRIN (sEMMPRIN) levels were assessed by ELISA. Results Echocardiographic assessment at 12 and 20 weeks of age confirmed significantly dilated aortic root in Fbn1C1039G/+ vs WT (mean±SD at 12 weeks: 1.772±0.081 vs 1.394±0.068 mm, respectively, p&amp;lt;0.0001; 20 weeks: 1.899±0.103 vs 1.520±0.083 mm, respectively, p&amp;lt;0.0001), and revealed that Fbn1C1039G/+-Bsg+/− mice had lower aortic root diameter extent compared to Fbn1C1039G/+ (12 weeks: 1.667±0.109 vs 1.772±0.081 mm, respectively, p=0.026; 20 weeks: 1.752±0.129 vs 1.899±0.103 mm, respectively, p=0.011). Pro-fibrotic gene profiling in a subset of 12 weeks old mice showed that Col1A1, Col3A1 and FN1 genes were more expressed in Fbn1C1039G/+ than in WT mice and that the up-regulation of these genes was mitigated in Fbn1C1039G/+ by Bsg depletion (ANOVA p=0.048, p=0.055, and p=0.0003, respectively). Moreover, we found a significant activation of the EMMPRIN downstream pro-fibrotic ERK1/2 pathway in Fbn1C1039G/+ compared to WT mice which was attenuated in the Fbn1C1039G/+-Bsg+/− model (p=0.030). Plasma sEMMPRIN levels were lower in Fbn1C1039G/+ than in WT mice, consistent with what we previously observed in MFS patients [5], and decreased over time in both Fbn1C1039G/+ and WT mice (2-way ANOVA disease p=0.013, time p=0.012, interaction p=ns). Conclusions Basigin genetic depletion reduces dilatation of the aortic root and pro-fibrotic pathway activation in a preclinical MFS model, confirming previous proof-of-concept findings and paving the way for the development of innovative therapies for MFS patients. Plasma sEMMPRIN levels stand as promising tool to predict the aortic enlargement progression in MFS models and patients. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Italian Ministery of Health

Understanding idiopathic pulmonary fibrosis - Clinical features, molecular mechanism and therapies.

Idiopathic pulmonary fibrosis (IPF) is a chronic lung fibrosing disease with high prevalence that has a prognosis worse than many cancers. There has been a recent influx of new observations aimed at explaining the mechanisms responsible for the initiation and progression of pulmonary fibrosis. However, despite this, the pathogenesis of the disease is largely unclear. Recent progress has been made in the characterization of specific pathologic and clinical features that have enhanced the understanding of pathologically activated molecular pathways during the onset and progression of IPF. This review highlights several of the advances that have been made and focus on the pathobiology of IPF. The work also details the different factors that are responsible for the disposition of the disease - these may be internal factors such as cellular mechanisms and genetic alterations, or they may be external factors from the environment. The changes that primarily occur in epithelial cells and fibroblasts that lead to the activation of profibrotic pathways are discussed in depth. Finally, a complete repertoire of the treatment therapies that have been used in the past as well as future medications and therapies is provided.

The Th17/IL-17 Axis and Kidney Diseases, With Focus on Lupus Nephritis.

Systemic lupus erythematosus (SLE) is a disease characterized by dysregulation and hyperreactivity of the immune response at various levels, including hyperactivation of effector cell subtypes, autoantibodies production, immune complex formation, and deposition in tissues. The consequences of hyperreactivity to the self are systemic and local inflammation and tissue damage in multiple organs. Lupus nephritis (LN) is one of the most worrying manifestations of SLE, and most patients have this involvement at some point in the course of the disease. Among the effector cells involved, the Th17, a subtype of T helper cells (CD4+), has shown significant hyperactivation and participates in kidney damage and many other organs. Th17 cells have IL-17A and IL-17F as main cytokines with receptors expressed in most renal cells, being involved in the activation of many proinflammatory and profibrotic pathways. The Th17/IL-17 axis promotes and maintains repetitive tissue damage and maladaptive repair; leading to fibrosis, loss of organ architecture and function. In the podocytes, the Th17/IL-17 axis effects include changes of the cytoskeleton with increased motility, decreased expression of health proteins, increased oxidative stress, and activation of the inflammasome and caspases resulting in podocytes apoptosis. In renal tubular epithelial cells, the Th17/IL-17 axis promotes the activation of profibrotic pathways such as increased TGF-β expression and epithelial-mesenchymal transition (EMT) with consequent increase of extracellular matrix proteins. In addition, the IL-17 promotes a proinflammatory environment by stimulating the synthesis of inflammatory cytokines by intrinsic renal cells and immune cells, and the synthesis of growth factors and chemokines, which together result in granulopoiesis/myelopoiesis, and further recruitment of immune cells to the kidney. The purpose of this work is to present the prognostic and immunopathologic role of the Th17/IL-17 axis in Kidney diseases, with a special focus on LN, including its exploration as a potential immunotherapeutic target in this complication.

Nebulized curcumin protects neonatal lungs from antenatal insult in rats.

Intrauterine growth restriction (IUGR) increases the risk of bronchopulmonary dysplasia (BPD), one of the major complications of prematurity. Antenatal low-protein diet (LPD) exposure in rats induces IUGR and mimics BPD-related alveolarization disorders. Peroxisome proliferator-activated receptor-γ (PPARγ) plays a key role in normal lung development and was found deregulated following LPD exposure. The objective of this article was to investigate the effects of nebulized curcumin, a natural PPARγ agonist, to prevent IUGR-related abnormal lung development. We studied rat pups antenatally exposed to an LPD or control diet (CTL) and treated with nebulized curcumin (50 mg/kg) or vehicle from postnatal (P) days 1 to 5. The primary readouts were lung morphometric analyses at P21. Immunohistochemistry (P21) and microarrays (P6 and P11) were compared within animals exposed to LPD versus controls, with and without curcumin treatment. Quantitative morphometric analyses revealed that LPD induced abnormal alveolarization as evidenced by a significant increase in mean linear intercept (MLI) observed in P21 LPD-exposed animals. Early curcumin treatment prevented this effect, and two-way ANOVA analysis demonstrated significant interaction between diet and curcumin both for MLI [F(1,39) = 12.67, P = 0.001] and radial alveolar count at P21 [F(1,40) = 6.065, P = 0.0182]. Immunohistochemistry for fatty acid binding protein 4 (FABP4), a major regulator of PPARγ pathway, showed a decreased FABP4+ alveolar cell density in LPD-exposed animals treated by curcumin. Transcriptomic analysis showed that early curcumin significantly prevented the activation of profibrotic pathways observed at P11 in LPD-exposed animals. Nebulized curcumin appears to be a promising strategy to prevent alveolarization disorders in IUGR rat pups, targeting pathways involved in lung development.

Increased CXCL4 expression in hematopoietic cells links inflammation and progression of bone marrow fibrosis in MPN

AbstractPrimary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) that leads to progressive bone marrow (BM) fibrosis. Although the cellular mutations involved in the pathogenesis of PMF have been extensively investigated, the sequential events that drive stromal activation and fibrosis by hematopoietic–stromal cross-talk remain elusive. Using an unbiased approach and validation in patients with MPN, we determined that the differential spatial expression of the chemokine CXCL4/platelet factor-4 marks the progression of fibrosis. We show that the absence of hematopoietic CXCL4 ameliorates the MPN phenotype, reduces stromal cell activation and BM fibrosis, and decreases the activation of profibrotic pathways in megakaryocytes, inflammation in fibrosis-driving cells, and JAK/STAT activation in both megakaryocytes and stromal cells in 3 murine PMF models. Our data indicate that higher CXCL4 expression in MPN has profibrotic effects and is a mediator of the characteristic inflammation. Therefore, targeting CXCL4 might be a promising strategy to reduce inflammation in PMF.

Selective Targeting of Calcineurin Isoforms by Calcineurin Inhibitors

BackgroundCalcineurin Inhibitors (CNIs) have increased one‐year and five‐year post‐transplantation survival rates to ~90% and ~75%, respectively. While CNIs have dramatically improved the quality of patient care, its side effects are also noteworthy: Long‐term CNI therapy is nephrotoxic and is a growing concern for clinicians and patients. To address this concern, voclosporin, a newer generation CNI, was developed and has been reported to ameliorate the nephrotoxic side effects noted in its predecessors. Studies are necessary to investigate this phenomenon further. Research into calcineurin (CnA) activity has identified distinct actions of two main isoforms: CnAα and CnAβ. CnAα is required for kidney function, whereas CnAβ predominantly modulates the immune response. It is widely accepted that cyclosporin A and tacrolimus have similar inhibitory activity against both isoforms, while there is no published data on voclosporin selectivity for calcineurin isoforms. Moreover, the degree of isoform selectivity and mechanisms of CNI‐induced renal impairment still remains unknown. Investigating CNI dose‐dependent selective binding between catalytic isoforms will provide clues for further studies to narrow in on mechanisms by which the inhibition of calcineurin causes renal fibrosis.HypothesisIt is well established that long‐term CNI treatment causes an increase in profibrotic markers leading to renal fibrosis. It has also been established that the most predominant catalytic isoform expressed in the kidney is CnAa. The objectives of this study are to investigate whether CNI treatment is more selective for CnAa than CnAb in the kidney, and that CnAa inhibition promotes fibrosis via a TGFβ‐mediated cell signaling pathway.Experimental DesignTo determine dose‐dependent isoform selectivity of CNIs, wild‐type mice renal cortical fibroblasts (WT FB) were treated with varying doses of either vehicle (100% ethanol) or CNI (tacrolimus, cyclosporin or voclosporin) for 24 hours. Cell lysates were collected and calmodulin pull‐down assays were carried out for western blot analysis to analyze expression of activated and total calcineurin isoforms.ResultsCNI treatment decreases activation of calcineurin isoforms in a dose‐dependent manner. Notably, there were striking differences in isoform activity with tacrolimus treatment versus cyclosporin and voclosporin. Additionally, CNIs altered expression of calcineurin isoforms and profibrotic markers.ConclusionsTogether, these results demonstrate that 1) isoform selectivity differs amongst each CNI, 2) inhibiting calcineurin isoforms affects total protein expression and 3) CNIs have distinct profibrotic profiles.SignificanceThis study begins to characterize the behavior of two main active calcineurin isoforms with varying doses of CNI treatment. CNI selectivity for calcineurin isoforms directs future studies investigating molecular culprits and signaling pathways involved in CNI‐induced renal damage. Development of future CNIs targeting specific calcineurin isoforms will bypass activation of profibrotic pathways that diminish renal function with long‐term CNI use.Support or Funding InformationAHA‐16SDG27080009 and NIH‐R21DK119879

What have we learned from basic science studies on idiopathic pulmonary fibrosis?

Idiopathic pulmonary fibrosis is a fatal age-related lung disease characterised by progressive and irreversible scarring of the lung. Although the details are not fully understood, there has been tremendous progress in understanding the pathogenesis of idiopathic pulmonary fibrosis, which has led to the identification of many new potential therapeutic targets. In this review we discuss several of these advances with a focus on genetic susceptibility and cellular senescence primarily affecting epithelial cells, activation of profibrotic pathways, disease-enhancing fibrogenic cell types and the role of the remodelled extracellular matrix.

Chronic inhalation of e-cigarette vapor containing nicotine disrupts airway barrier function and induces systemic inflammation and multiorgan fibrosis in mice.

Electronic (e)-cigarettes theoretically may be safer than conventional tobacco. However, our prior studies demonstrated direct adverse effects of e-cigarette vapor (EV) on airway cells, including decreased viability and function. We hypothesize that repetitive, chronic inhalation of EV will diminish airway barrier function, leading to inflammatory protein release into circulation, creating a systemic inflammatory state, ultimately leading to distant organ injury and dysfunction. C57BL/6 and CD-1 mice underwent nose only EV exposure daily for 3-6 mo, followed by cardiorenal physiological testing. Primary human bronchial epithelial cells were grown at an air-liquid interface and exposed to EV for 15 min daily for 3-5 days before functional testing. Daily inhalation of EV increased circulating proinflammatory and profibrotic proteins in both C57BL/6 and CD-1 mice: the greatest increases observed were in angiopoietin-1 (31-fold) and EGF (25-fold). Proinflammatory responses were recapitulated by daily EV exposures in vitro of human airway epithelium, with EV epithelium secreting higher IL-8 in response to infection (227 vs. 37 pg/ml, respectively; P < 0.05). Chronic EV inhalation in vivo reduced renal filtration by 20% ( P = 0.017). Fibrosis, assessed by Masson's trichrome and Picrosirius red staining, was increased in EV kidneys (1.86-fold, C57BL/6; 3.2-fold, CD-1; P < 0.05), heart (2.75-fold, C57BL/6 mice; P < 0.05), and liver (1.77-fold in CD-1; P < 0.0001). Gene expression changes demonstrated profibrotic pathway activation. EV inhalation altered cardiovascular function, with decreased heart rate ( P < 0.01), and elevated blood pressure ( P = 0.016). These data demonstrate that chronic inhalation of EV may lead to increased inflammation, organ damage, and cardiorenal and hepatic disease.

Serum metabolic profiling identified a distinct metabolic signature in patients with idiopathic pulmonary fibrosis \u2013 a potential biomarker role for LysoPC

BackgroundIdiopathic pulmonary fibrosis (IPF) is a lethal lung disease of unknown etiology. Patients present loss of lung function, dyspnea and dry cough. Diagnosis requires compatible radiologic imaging and, in undetermined cases, invasive procedures such as bronchoscopy and surgical lung biopsy. The pathophysiological mechanisms of IPF are not completely understood. Lung injury with abnormal alveolar epithelial repair is thought to be a major cause for activation of profibrotic pathways in IPF. Metabolic signatures might indicate pathological pathways involved in disease development and progression. Reliable serum biomarker would help to improve both diagnostic approach and monitoring of drug effects.MethodThe global metabolic profiles measured by ultra high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) of ten stable IPF patients were compared to the ones of ten healthy participants. The results were validated in an additional study of eleven IPF patients and ten healthy controls.ResultsWe discovered 10 discriminative metabolic features using multivariate and univariate statistical analysis. Among them, we identified one metabolite at a retention time of 9.59 min that was two times more abundant in the serum of IPF patients compared to healthy participants. Based on its ion pattern, a lysophosphatidylcholine (LysoPC) was proposed. LysoPC is a precursor of lysophosphatidic acid (LPA) – a known mediator for lung fibrosis with its pathway currently being evaluated as new therapeutic drug target for IPF and other fibrotic diseases.ConclusionsWe identified a LysoPC by UHPLC-HRMS as potential biomarker in serum of patients with IPF. Further validation studies in a larger cohort are necessary to determine its role in IPF.Trial RegistrationSerum samples from IPF patients have been obtained within the clinical trial NCT02173145 at baseline and from the idiopathic interstitial pneumonia (IIP) cohort study. The study was approved by the Swiss Ethics Committee, Bern (KEK 002/14 and 246/15 or PB_2016–01524).

Activation of TGF-β1/α-SMA/Col I Profibrotic Pathway in Fibroblasts by Galectin-3 Contributes to Atrial Fibrosis in Experimental Models and Patients

Background/Aims: This study aimed to evaluate whether galectin-3 (Gal-3) contributes actively to atrial fibrosis both in patients and experimental atrial fibrillation (AF) models. Methods: Mouse HL-1 cardiomyocytes were subjected to rapid electrical stimulation (RES) to explore Gal-3 expression and secretion levels by western blotting (WB) and enzyme linked immunosorbent assay (ELISA). Neonatal rat cardiac fibroblasts were treated with conditioned culture medium and recombinant human Gal-3 to evaluate the activation of the transforming growth factor (TGF)-β1/α-smooth muscle actin (SMA)/collagen I (Col I) profibrotic pathway (WB) and fibroblast proliferation with a Cell Counting Kit-8 (CCK-8). Furthermore, in the rapid atrial pacing (RAP) rabbit AF model, atrial Gal-3 expression and its effects on the profibrotic pathway were evaluated (WB and Masson’s trichrome staining). Moreover, 44 consecutive patients who underwent single mitral valve repair/replacement were included, consisting of 28 patients with persistent AF (PeAF) and 16 with sinus rhythm (SR). Coronary sinus blood was also sampled to test circulating Gal-3 levels (ELISA), and atrial myocardium Gal-3 and its downstream TGF-β1/α-SMA pathway were also measured by WB and immunohistochemical staining. Results: Gal-3 expression in HL-1 cells and its secretion level in culture medium were greatly increased after 24 h RES. Treatment of neonatal rat cardiac fibroblasts with conditioned media collected from the RES group or recombinant human Gal-3 protein (10 and 30 µg/mL) for 72 h induced the activation of the TGF-β1/α-SMA/Col I profibrotic pathway. RAP increased Gal-3 levels and activated the TGF-β1/α-SMA/Col I pathway in rabbit left atria, while the Gal-3 inhibitor N-acetyllactosamine, injected at 4.5 mg/kg every 3 days, mitigated these adverse changes. Furthermore, Gal-3 levels in coronary sinus blood samples and myocardial Gal-3 expression levels were higher in the PeAF patients than in the SR patients, and higher level profibrotic pathway activation was also confirmed. Conclusions: Activation of Gal-3 expression in the atria can subsequently activate the TGF-β1/α-SMA/Col I pathway in cardiac fibroblasts, which may enhance atrial fibrosis.

Abstract P193: Anti-fibrotic and Anti-oxidant Actions of a Muscadine Grape Extract Supplement on Hypertension-induced Cardiac Damage

Approximately 75 million U.S. adults suffer from hypertension, an independent risk factor for pathological cardiac hypertrophy. The current study examines the effects of a muscadine grape extract formulation (MGE; Piedmont Research &amp; Development Corp.) with anti-oxidant, anti-inflammatory, and anti-proliferative properties on hypertension-induced cardiac damage in Sprague-Dawley rats receiving a 4-week Ang II infusion (24 μg/kg/h). We previously showed that MGE in the drinking water had no effect on blood pressure or systolic function in normotensive or hypertensive rats; however, MGE ameliorated the Ang II-induced decrease in diastolic function and increase in cardiomyocyte cross-sectional area. In the current study, MGE supplementation of Ang II-treated rats decreased interstitial cardiac fibrosis, reducing collagen III staining in the myocardium (0.9 ± 0.2% control, 6.8 ± 1.0% Ang II, and 2.8 ± 0.4% Ang II/MGE; p&lt;0.01). MGE alone had no effect on any parameters assessed. The positive correlation between collagen and diastolic function with Ang II compared to control (p&lt;0.01) was significantly abrogated by co-administration of MGE. TGFβ is a critical cytokine that stimulates cardiac fibrosis. The Ang II-mediated increase in cardiac TGFβ mRNA was attenuated by MGE (relative gene expression: 1.0 ± 0.1 control, 2.0 ± 0.4 Ang II, 1.1 ± 0.2 Ang II/MGE; p&lt;0.05) as was downstream pSmad2 protein in cardiomyocytes (% nuclei: 26.1 ± 6 control, 53.8 ± 9.6 Ang II, 27.6 ± 5.5 Ang II/MGE; p&lt;0.05) and cardiac fibroblasts (2.3 ± 1.1 control, 11.7 ± 4.9 Ang II, 2.2 ± 0.5 Ang II/MGE; p&lt;0.05). NADPH oxidase is a primary contributor to cardiac oxidative stress and excess ROS production can lead to activation of pro-fibrotic pathways. MGE significantly reduced the Ang II-induced increase in p22phox mRNA (relative gene expression: 1.0 ± 0.1 control, 1.9 ± 0.1 Ang II, 1.0 ± 0.1 Ang II/MGE; p&lt;0.0001) and protein (relative density: 1.0 ± 0.2 control, 5.4 ± 1.6 Ang II, 2.9 ± 1.0 Ang II/MGE; p&lt;0.05), a subunit required for NADPH oxidase activity. These results indicate that MGE ameliorates cardiac fibrosis by targeting NADPH oxidase and the TGFβ pro-fibrotic pathway, suggesting that MGE supplementation may be an effective, natural therapeutic for hypertension-induced cardiac damage.

Nicotinic receptors in chronic kidney disease

Tobacco smoking remains the most important modifiable risk factor for improving overall morbidity and mortality. In addition to being a risk factor for cancer, cardiovascular and lung diseases, strong evidence from human and animal studies has demonstrated that cigarette smoking accelerates the progression of chronic kidney disease (CKD). Clinical studies have shown a strong association between cigarette smoking and worsening CKD in patients with diabetes mellitus, hypertension, polycystic kidney disease, and post kidney transplant. Nicotine, in addition to being responsible for the addictive properties of cigarette smoking, also has other important biological effects on a variety of organs and tissues. In humans, nicotine induces transitory increases in blood pressure accompanied by reductions in glomerular filtration rate and effective renal plasma flow. In animals, nicotine increases the severity of renal injury in subjects with diabetic nephropathy, CKD, and acute kidney injury (AKI). These effects of nicotine on the kidney are linked to increased generation of reactive oxygen species and activation of pro-fibrotic pathways. There are several nicotinic acetylcholine receptor (nAChR) subunits which are expressed in the normal kidney, and the specific blockade of α7-subunit ameliorates the effects of nicotine in animal models with CKD. In summary, the clinical and experimental evidence indicates that nicotine, via the activation of specific nAChRs, is partly responsible for the deleterious effects of cigarette smoking in the progression of CKD. Better understanding of these mechanisms may result in the development of novel strategies to ameliorate the effects of cigarette smoking in CKD.

Epidermal growth factor receptor signaling mediates aldosterone-induced profibrotic responses in kidney

Aldosterone has been recognized as a risk factor for the development of chronic kidney disease (CKD). Studies have indicated that enhanced activation of epidermal growth factor receptor (EGFR) is associated with the development and progression of renal fibrosis. But if EGFR is involved in aldosterone-induced renal fibrosis is less investigated. In the present study, we examined the effect of erlotinib, an inhibitor of EGFR tyrosine kinase activity, on the progression of aldosterone-induced renal profibrotic responses in a murine model underwent uninephrectomy. Erlotinib-treated rats exhibited relieved structural lesion comparing with rats treated with aldosterone alone, as characterized by glomerular hypertrophy, mesangial cell proliferation and expansion. Also, erlotinib inhibited the expression of TGF-β, α-SMA and mesangial matrix proteins such as collagen Ⅳ and fibronectin. In cultured mesangial cells, inhibition of EGFR also abrogated aldosterone-induced expression of extracellular matrix proteins, cell proliferation and migration. We also demonstrated that aldosterone induced the phosphorylation of EGFR through generation of ROS. And the activation of EGFR resulted in the phosphorylation of ERK1/2, leading to the activation of profibrotic pathways. Taken together, we concluded that aldosterone-mediated tissue fibrosis relies on ROS induced EGFR/ERK activation, highlighting EGFR as a potential therapeutic target for modulating renal fibrosis.