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Effects of Osteopontin on Collagen Gene Expression and Smooth Muscle Alpha Actin Protein in Human Lung Fibroblasts (A) Northern blot of 20 l g total cellular RNA per lane extracted from control and fibroblasts stimulated with 0.4 l g/ml and 1 l g/ml osteopontin. Both concentrations of osteopontin induced an up- regulation in the expression of a 1 type I collagen. (B) Western blot showing no effect of osteopontin on immunoreactive a smooth muscle actin. Recombinant TGF- b 1 was used as a positive control. C, control; OPN, osteopontin. DOI: 10.1371/journal.pmed.0020251.g008
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Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal disorder characterized by fibroproliferation and excessive accumulation of extracellular matrix in the lung.
Using oligonucleotide arrays, we identified osteopontin as one of the genes that significantly distinguishes IPF from normal lungs. Osteopontin was localized to alveolar epithel...
Contexts in source publication
Context 1
... induces collagen gene expression in fibro- blasts. The effect of osteopontin on collagen gene expression is depicted in Figure 8. Northern blot analysis ( Figure 8A) revealed a 2-fold increase in a1 type I collagen gene expression. ...
Context 2
... induces collagen gene expression in fibro- blasts. The effect of osteopontin on collagen gene expression is depicted in Figure 8. Northern blot analysis ( Figure 8A) revealed a 2-fold increase in a1 type I collagen gene expression. Expression of a-smooth muscle actin in fibroblasts was induced by TGF-b1 but not by osteopontin ( Figure 8B). ...
Context 3
... effect of osteopontin on collagen gene expression is depicted in Figure 8. Northern blot analysis ( Figure 8A) revealed a 2-fold increase in a1 type I collagen gene expression. Expression of a-smooth muscle actin in fibroblasts was induced by TGF-b1 but not by osteopontin ( Figure 8B). ...
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Citations
... OPN expression is associated with fibrosis, acting as a chemotactic factor for fibroblasts, modulating the secretion of metalloproteinases (MMPs), and regulating the production of the transforming growth factor (TGF)β [10,11]. However, little is known about the role of OPN in ILDs. ...
... Along with surfactant protein-D (SP-D) and MMP-7, it can enhance the accuracy of the differential diagnosis in patients with IPF, compared with non-IPF ILDs [13]. Additionally, OPN is the most up-regulated gene in the lungs of patients with IPF (levels up to 20-fold higher than in healthy lungs), and OPN levels in BAL fluid are higher in IPF patients than in healthy controls [11]. In patients with anti-MDA5 antibodypositive dermatomyositis-associated with ILD, OPN is overexpressed in epithelial cells and macrophages; therefore, it could be used as a prognostic marker [14]. ...
Osteopontin (OPN) is a glycoprotein involved in Th1 and Th17 differentiation, and inflammation and tissue remodeling. OPN is a biomarker of disease activity in patients with autoimmune inflammatory conditions. This study aimed to assess the diagnostic and prognostic value of OPN in interstitial lung diseases (ILDs). Between May 2016 and October 2019, 344 patients with ILD were recruited at the Hospital Universitario Marqués de Valdecilla (Spain) and were prospectively followed-up. This study involved the determination of OPN serum levels by ELISA and OPN RNA expression quantified using qPCR. Six genetic polymorphisms in OPN (rs28357094, rs2853749, rs2853750, rs11728697, rs7695531, and rs1126616) were genotyped using TaqMan assays. OPN serum levels were also assessed in 140 healthy controls. OPN serum levels (median [interquartile range]) were significantly higher in ILD patients than in controls (1.05 [0.75–1.51] ng/mL versus 0.81 [0.65–0.98] ng/mL in healthy controls; p < 0.01). OPN serum levels were inversely correlated with the forced vital capacity. OPN serum levels were also higher in ILD patients who died or underwent lung transplantation when compared with the remaining ILD patients (1.15 [0.80–1.72] ng/mL versus 0.99 [0.66–1.32] ng/mL; p = 0.05). Survival worsened in ILD patients with OPN > 1.03 ng/mL at 1, 3, and 5 years. No statistically significant differences in the genetic frequencies of OPN polymorphisms or the RNA expression were found among the different ILD groups. Elevated levels of OPN in the serum may be a useful indicator in identifying patients with ILD who are more likely to experience poor outcomes.
... 52 Osteopontin (SPP1), mesothelin (MSLN) and bone morphogenetic protein 4 are all profibrotic mediators whose expression was also increased in SSc lung pericytes. [53][54][55] Although the expression of several collagens was noted, we did not observe differential transcriptional changes in collagen I and III and iScience Article ⍺-smooth muscle actin in SSc lung pericytes as compared to NORML. These results contrast with the findings by Valenzi et al., who documented an increase in COL1A2 and COL3A1 transcripts relative to control pericytes. ...
... With increasing sample sizes and commensurate increasing statistical power, these studies have highlighted the extensive changes in the cellular makeup and molecular programs of PF. In one of the first microarray studies of IPF lungs, osteopontin (SPP1) upregulation was observed and shown to activate profibrotic signaling in epithelial cells and fibroblasts [118]. Another early study sought to explore differences between sporadic and familial PF. ...
... In SSc-ILD, MMP7 has been shown to be expressed in alveolar type II cells and bronchial epithelium in a similar fashion to IPF lung tissue (42). Similarly, SPP1, KRT17, and CDH3, which are upregulated in SSc-ILD, have all been described to be dysregulated in IPF (43)(44)(45)(46). Telomere dysfunction and shortened telomeres are a hallmark of IPF pathogenesis (11,14,15). ...
Aging and cellular senescence are increasingly recognized as key contributors to pulmonary fibrosis. However, our understanding in the context of scleroderma-associated interstitial lung disease (SSc-ILD) is limited. To investigate, we leveraged previously established lung aging- and cell-specific senescence signatures to determine their presence and potential relevance to SSc-ILD. We performed a gene expression meta-analysis of lung tissues from 38 SSc-ILD and 18 healthy controls and found that markers (GDF15, COMP, and CDKN2A) and pathways (p53) of senescence were significantly increased in SSc-ILD. When probing the established aging and cellular senescence signatures, we found that epithelial and fibroblast senescence signatures had a 3.6- and 3.7-fold enrichment, respectively, in the lung tissue of SSc-ILD and that lung aging genes (CDKN2A, FRZB, PDE1A, and NAPI12) were increased in SSc-ILD. These signatures were also enriched in SSc skin and associated with degree of skin involvement (limited vs. diffuse cutaneous). To further support these findings, we examined telomere length (TL), a surrogate for aging, in the lung tissue and found that, independent of age, SSc-ILD had significantly shorter telomeres than controls in type II alveolar cells in the lung. TL in SSc-ILD was comparable to idiopathic pulmonary fibrosis, a disease of known aberrant aging. Taken together, this study provides novel insight into the possible mechanistic effects of accelerated aging and aberrant cellular senescence in SSc-ILD pathogenesis.
... The underlying mechanisms of post-acuteCOVID-19 sequelae remain elusive [3,12]. Osteopontin (OPN) is a glycoprotein normally expressed in several tissues and is involved in a variety of human diseases [13], including severe influenza infection [14] and idiopathic pulmonary fibrosis [15,16]. In acute COVID-19, high circulating OPN levels have been associated with an increased risk of death or the need for mechanical ventilation [17] and increased levels of OPN at admission were shown to predict disease progression [18]. ...
COVID-19 survivors commonly report persistent symptoms. In this observational study, we investigated the link between osteopontin (OPN) and post-acute COVID-19 symptoms and lung functional/imaging abnormalities. We recorded symptoms and lung imaging/functional data from previously hospitalized COVID-19 patients, who were followed for 4–84 weeks (122 patients/181 visits) post-symptom onset at our outpatient clinic. Circulating OPN was determined using ELISA. Plasma OPN levels were higher in symptomatic patients (compared with the asymptomatic ones); those with dyspnea (compared with those without dyspnea);those with a combination of serious symptoms, i.e., the presence of at least one of the following: dyspnea, fatigue and muscular weakness (compared with those with none of these symptoms); and those with dyspnea and m-MRC > 1 (compared with those with m-MRC = 0–1). Plasma OPN levels were inversely correlated with EQ-VAS (visual analog scale of the EQ-5D-5L health-related quality-of-life questionnaire) values. High-resolution CT or diffusion lung capacity (DLCO) findings were not related to circulating OPN. In the multiple logistic regression, the presence of symptoms, dyspnea, or the combination of serious symptoms were linked to female gender, increased BMI and pre-existing dyspnea (before the acute disease), while increased plasma OPN levels, female gender and pre-existing dyspnea with m-MRC > 1 were independently associated with severe post-COVID-19 dyspnea (m-MRC > 1). Using a correlation matrix to investigate multiple correlations between EQ-VAS, OPN and epidemiological data, we observed an inverse correlation between the OPN and EQ-VAS values. Increased circulating OPN was linked to the persistence of severe exertional dyspnea and impaired quality of life in previously hospitalized COVID-19 patients.
... BAL was performed as described 25 . Briefly, BAL was performed through flexible fiberoptic bronchoscopy under local anesthesia and 300 ml of normal saline were instilled in 50-ml aliquots, with an average recovery of 60-70%. ...
Hypersensitivity Pneumonitis (HP) is an immune-mediated interstitial lung disease (ILD) characterized by fibrotic HP (fHP) or non-fibrotic HP (non-fHP). Fibrosis is associated with poor prognosis, emphasizing the need for biomarkers to distinguish fHP from non-fHP. This study aimed to determine the plasma levels of GDF15 in HP patients and assess its association with lung function and phenotype classification. GDF15 levels were quantified by ELISA in HP (n = 64), idiopathic pulmonary fibrosis (n = 54), and healthy control (n = 128) groups. Clinical, demographic, and functional data were obtained from medical records. High-resolution chest CT scans were used to classify HP patients into fHP and non-fHP groups. In addition, receiver operating characteristic analysis was performed to determine the cut-off point, sensitivity, and specificity. Our results revealed significantly elevated GDF15 levels in fHP compared to non-fHP (2539 ± 821 pg/ml versus 1783 ± 801 pg/ml; p = 0.009). The estimated cut-off point for plasma GDF15 levels to distinguish fHP from non-fHP was 2193.4 pg/ml (AUC 0.75). These findings suggest that GDF15 may serve as a valuable biomarker for differentiating between fHP and non-fHP, potentially indicating its involvement in lung fibrosis development in HP.
... With the aim to identify potential drug targets that would enable the development of therapies for IPF, we performed a mRNA expression analysis comprising 8911 genes. Expression in lung tissues of 13 IPF patients was compared with controls from 11 healthy donors utilizing a gene dataset from the Gene Expression Omnibus (accession number: GSE2052) [40][41][42][43] . The genes were filtered based on statistical significance to calculate the differences in gene expression between healthy donors and IPF patients. ...
... The previously reported MRGPRX2 agonist proadrenomedullin N-terminal peptide-20 (PAMP-20; sequence: ARLDVASEFRKKWNKWALSR) was used as a positive control (see Supplementary Fig. 1a) As a next step, the selectivity of CXCL14 for MRGPRX2 versus the other MRGPRX subtypes, MRGPRX1, MRGPRX3, and Identification of a target receptor for CXCL14. a A volcano plot of gene expression (8912 genes) of healthy (11 lung samples) versus IPF (13 lung samples) groups displaying statistical significance (-log 10 p-value) versus magnitude of change (-log 2 fold change), using the online Gene Expression Omnibus database (GEO) and the Graphpad Prism software (accession number: GSE2052) [40][41][42][43] . Genes in the blue box are significantly upregulated in IPF patients with an adjusted p-value cut-off of 0.005 and a more than 4-fold change in expression, see Supplementary Data 1 for more details. ...
Patients with idiopathic pulmonary fibrosis show a strongly upregulated expression of chemokine CXCL14, whose target is still unknown. Screening of CXCL14 in a panel of human G protein-coupled receptors (GPCRs) revealed its potent and selective activation of the orphan MAS-related GPCR X2 (MRGPRX2). This receptor is expressed on mast cells and − like CXCL14 − upregulated in bronchial inflammation. CXCL14 induces robust activation of MRGPRX2 and its putative mouse ortholog MRGPRB2 in G protein-dependent and β-arrestin recruitment assays that is blocked by a selective MRGPRX2/B2 antagonist. Truncation combined with mutagenesis and computational studies identified the pharmacophoric sequence of CXCL14 and its presumed interaction with the receptor. Intriguingly, C-terminal domain sequences of CXCL14 consisting of 4 to 11 amino acids display similar or increased potency and efficacy compared to the full CXCL14 sequence (77 amino acids). These results provide a rational basis for the future development of potential idiopathic pulmonary fibrosis therapies.
... [15] The mechanism by which OPN, a predominant Th1 cytokine (antifibrotic), demonstrates a profibrotic effect is not clear. [16] This protein was shown to be elevated in histological sections of several types of human precancer tissues compared with normal tissue. [17] Many studies have shown that inflammatory mediators and growth factors, such as TNF-1, IL-1 and PDGF, play a role in the upregulation of OPN in OPMDs. ...
Background: Inflammatory cells and cytokines in the chronically injured mucosa promote fibrosis in the oral
submucous fibrosis (OSF) fibrotic milieu. Osteopontin (OPN) is a wound-healing mediator that upregulates
the inflammatory response and is involved in the malignancy and fibrosis of multiple organ systems.
Objectives: We investigated the expression of OPN in oral potentially malignant disorders (OPMDs) and
oral squamous cell carcinomas (OSCCs) to determine its role in the malignant transformation and fibrosis
of oral tissues. The expression of OPN in OPMDs and OSCCs was compared and correlated, and the role of
OPN as a fibrotic mediator in OSF was explained.
Study Design: A total of 30 cases of normal mucosa and OPMDs (mild dysplasia, severe dysplasia, OSF and
OSCCs) were studied by purposive sampling. In these groups, OPN immunoreactivity was examined and
correlated with clinical findings.
Results: In mild dysplasia, OPN expression was restricted to the basal cell layer with moderate staining
intensity. In severe dysplasia, it was extremely intense and extended throughout the epithelium. In the
OSF, OPN expression was moderate in the perinuclear areas of the basal cell layer. The expression of OPN
was very strong in OSCC. A flow diagram explaining the profibrotic role of OPN in OSF has been provided.
Conclusion: A positive role of OPN in both pathogenesis and malignant transformation of OPMDs and
OSCC has been demonstrated
... Likewise, upregulation of OPN was also observed in animals with bleomycin-induced pulmonary fibrosis [62][63][64]. In IPF lungs, macrophages, and epithelial cells are suggested to be the major sources of OPN production [7,63,65]. The proliferation, migration, and adhesion of fibroblasts followed by ECM (e.g., collage) accumulation are significantly enhanced by OPN treatment [7,63,65]. ...
... In IPF lungs, macrophages, and epithelial cells are suggested to be the major sources of OPN production [7,63,65]. The proliferation, migration, and adhesion of fibroblasts followed by ECM (e.g., collage) accumulation are significantly enhanced by OPN treatment [7,63,65]. OPN can also promote the proliferation and migration of alveolar epithelial cells [65]. Moreover, transforming growth factor-β1 (TGF-β1)-mediated EMT plays an important role in the pathogenesis of IPF [61]. ...
... The proliferation, migration, and adhesion of fibroblasts followed by ECM (e.g., collage) accumulation are significantly enhanced by OPN treatment [7,63,65]. OPN can also promote the proliferation and migration of alveolar epithelial cells [65]. Moreover, transforming growth factor-β1 (TGF-β1)-mediated EMT plays an important role in the pathogenesis of IPF [61]. ...
Osteopontin (OPN) is a multifunctional phosphorylated protein that is involved in physiological and pathological events. Emerging evidence suggests that OPN also plays a critical role in the pathogenesis of respiratory diseases. OPN can be produced and secreted by various cell types in lungs and overexpression of OPN has been found in acute lung injury/acute respiratory distress syndrome (ALI/ARDS), pulmonary hypertension (PH), pulmonary fibrosis diseases, lung cancer, lung infection, chronic obstructive pulmonary disease (COPD), and asthma. OPN exerts diverse effects on the inflammatory response, immune cell activation, fibrosis and tissue remodeling, and tumorigenesis of these respiratory diseases, and genetic and pharmacological moudulation of OPN exerts therapeutic effects in the treatment of respiratory diseases. In this review, we summarize the recent evidence of multifaceted roles and underlying mechanisms of OPN in these respiratory diseases, and targeting OPN appears to be a potential therapeutic intervention for these diseases.
... Osteopontin is a matricellular protein produced by macrophages that induces fibroblast migration, proliferation, and adhesion [38]. It is upregulated in bronchoalveolar lavage fluid of IPF patients and co-localizes with MMP-7 in alveolar epithelial cells in IPF lungs [39]. Previous studies have indicated that IPF patients and patients with alternative idiopathic ILDs can be distinguished by SP-D >31 ng/ml, MMP-7 >1.75 ng/ml, and osteopontin >6 ng/ml. ...
Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial disease that cannot be cured, and treatment options for IPF are very limited. Early diagnosis, close monitoring of disease progression, and timely treatment are therefore the best options for patients due to the irreversibility of IPF. Effective markers help doctors judge the development and prognosis of disease. Recent research on traditional biomarkers (KL-6, SP-D, MMP-7, TIMPs, CCL18) has provided novel ideas for predicting disease progression and prognosis. Some emerging biomarkers (HE4, GDF15, PRDX4, inflammatory cells, G-CSF) also provide more possibilities for disease prediction. In addition to markers in serum and bronchoalveolar lavage fluid (BALF), some improvements related to the GAP model and chest HRCT also show good predictive ability for disease prognosis.
