SH2 Domain-Containing Phosphatase-2 Is a Novel Antifibrotic Regulator in Pulmonary Fibrosis

ADRB2 inhibition combined with antioxidant treatment alleviates lung fibrosis by attenuating TGFβ/SMAD signaling in lung fibroblasts

Idiopathic pulmonary fibrosis is a progressive and fatal interstitial lung disease with a poor prognosis and limited therapeutic options, which is characterized by aberrant myofibroblast activation and pathological remodeling of the extracellular matrix, while the mechanism remains elusive. In the present investigation, we observed a reduction in ADRB2 expression within both IPF and bleomycin-induced fibrotic lung samples, as well as in fibroblasts treated with TGF-β1. ADRB2 inhibition blunted bleomycin-induced lung fibrosis. Blockage of the ADRB2 suppressed proliferation, migration, and invasion and attenuated TGF-β1-induced fibroblast activation. Conversely, the enhancement of ADRB2 expression or functionality proved capable of inducing fibroblast-to-myofibroblast differentiation. Subsequent mechanistic investigation revealed that inhibition of ADRB2 suppressed the activation of SMAD2/3 in lung fibroblasts and increased phos-SMAD2/3 proteasome degradation, and vice versa. Finally, ADRB2 inhibition combined with antioxidants showed increased efficacy in the therapy of bleomycin-induced lung fibrosis. In short, these data indicate that ADRB2 is involved in lung fibroblast differentiation, and targeting ADRB2 could emerge as a promising and innovative therapeutic approach for pulmonary fibrosis.

Monocytes and macrophages: emerging mechanisms and novel therapeutic targets in pulmonary fibrosis

Pulmonary fibrosis results from a plethora of abnormal pathogenetic events. In idiopathic pulmonary fibrosis (IPF), inhalational, environmental, or occupational exposures in genetically and epigenetically predisposed individuals trigger recurrent cycles of alveolar epithelial cell injury, activation of coagulation pathways, chemoattraction, and differentiation of monocytes into monocyte-derived alveolar macrophages (Mo-AMs). When these events happen intermittently and repeatedly throughout the individual's life cycle, the wound repair process becomes aberrant leading to bronchiolization of distal air spaces, fibroblast accumulation, extracellular matrix deposition, and loss of the alveolar-capillary architecture. The role of immune dysregulation in IPF pathogenesis and progression has been underscored in the past mainly after the disappointing results of immunosuppressant use in IPF patients; however, recent reports highlighting the prognostic and mechanistic roles of monocytes and Mo-AMs revived the interest in immune dysregulation in IPF. In this review, we will discuss the role of these cells in the onset and progression of IPF, as well as potential targeted therapies.

SRC and TKS5 mediated podosome formation in fibroblasts promotes extracellular matrix invasion and pulmonary fibrosis

The activation and accumulation of lung fibroblasts resulting in aberrant deposition of extracellular matrix components, is a pathogenic hallmark of Idiopathic Pulmonary Fibrosis, a lethal and incurable disease. In this report, increased expression of TKS5, a scaffold protein essential for the formation of podosomes, was detected in the lung tissue of Idiopathic Pulmonary Fibrosis patients and bleomycin-treated mice. Τhe profibrotic milieu is found to induce TKS5 expression and the formation of prominent podosome rosettes in lung fibroblasts, that are retained ex vivo, culminating in increased extracellular matrix invasion. Tks5+/- mice are found resistant to bleomycin-induced pulmonary fibrosis, largely attributed to diminished podosome formation in fibroblasts and decreased extracellular matrix invasion. As computationally predicted, inhibition of src kinase is shown to potently attenuate podosome formation in lung fibroblasts and extracellular matrix invasion, and bleomycin-induced pulmonary fibrosis, suggesting pharmacological targeting of podosomes as a very promising therapeutic option in pulmonary fibrosis.

SHP2 promotes sarcoidosis severity by inhibiting SKP2-targeted ubiquitination of TBET in CD8+ T cells

Sarcoidosis is an interstitial lung disease (ILD) characterized by interferon-γ (IFN-γ) and T-box expressed in T cells (TBET) dysregulation. Although one-third of patients progress from granulomatous inflammation to severe lung damage, the molecular mechanisms underlying this process remain unclear. Here, we found that pharmacological inhibition of phosphorylated SH2-containing protein tyrosine phosphatase-2 (pSHP2), a facilitator of aberrant IFN-γ abundance, decreased large granuloma formation and macrophage infiltration in the lungs of mice with sarcoidosis-like disease. Positive treatment outcomes were dependent on the effective enhancement of TBET ubiquitination within CD8+ T cells. Mechanistically, we identified a posttranslational modification pathway in which the E3 F-box protein S-phase kinase-associated protein 2 (SKP2) targets TBET for ubiquitination in T cells under normal conditions. However, this pathway was disrupted by aberrant pSHP2 signaling in CD8+ T cells from patients with progressive pulmonary sarcoidosis and end-stage disease. Ex vivo inhibition of pSHP2 in CD8+ T cells from patients with end-stage sarcoidosis enhanced TBET ubiquitination and suppressed IFN-γ and collagen synthesis. Therefore, these studies provided new mechanistic insights into the SHP2-dependent posttranslational regulation of TBET and identified SHP2 inhibition as a potential therapeutic intervention against severe sarcoidosis. Furthermore, these studies also suggest that the small-molecule SHP2 inhibitor SHP099 might be used as a therapeutic measure against human diseases linked to TBET or ubiquitination.

SHP2 participates in decidualization by activating ERK to maintain normal nuclear localization of progesterone receptor

In brief

The establishment and maintenance of embryo implantation and pregnancy require decidualization of endometrial stromal cells. This paper reveals that SHP2 ensures the correct subcellular localization of progesterone receptor, thereby safeguarding the process of decidualization.

Abstract

Decidualization is the process of conversion of endometrial stromal cells into decidual stromal cells, which is caused by progesterone production that begins during the luteal phase of the menstrual cycle and then increases throughout pregnancy dedicated to support embryonic development. Decidualization deficiency is closely associated with various pregnancy complications, such as recurrent miscarriage (RM). Here, we reported that Src-homology-2-containing phospho-tyrosine phosphatase (SHP2), a key regulator in the signal transduction process downstream of various receptors, plays an indispensable role in decidualization. SHP2 expression was upregulated during decidualization. SHP2 inhibitor RMC-4550 and shRNA-mediated SHP2 reduction resulted in a decreased level of phosphorylation of ERK and aberrant cytoplasmic localization of progesterone receptor (PR), coinciding with reduced expression of IGFBP1 and various other target genes of decidualization. Solely inhibiting ERK activity recapitulated these observations. Administration of RMC-4550 led to decidualization deficiency and embryo absorption in mice. Moreover, reduced expression of SHP2 was detected in the decidua of RM patients. Our results revealed that SHP2 is key to PR's nuclear localization, thereby indispensable for decidualization and that reduced expression of SHP2 might be engaged in the pathogenesis of RM.

SH2 Domain-Containing Phosphatase-SHP2 Attenuates Fibrotic Responses through Negative Regulation of Mitochondrial Metabolism in Lung Fibroblasts

Background: We have previously shown that SHP2 downregulation may predispose fibroblasts to differentiate into myofibroblasts and proposed a role for SHP2 downregulation in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Recent data have shown that SHP2 localizes to the mitochondrial intercristae, and its overexpression enhances mitochondrial metabolism leading to oxidative stress and senescence. Objective: To determine the effect of SHP2 on fibrotic responses. Methods and Results: Primary mouse lung fibroblasts derived from mice carrying a conditional knock-in mutation (D61G/+), rendering the SHP2 catalytic domain constitutively active, had reduced proliferation (1.6-fold, p < 0.05), migration (2-fold, p < 0.05), as well as reduced responsiveness of TGFB-1 induced fibroblasts-to-myofibroblasts differentiation, compared to wild-type ones. Electron microscope analysis revealed that SHP2 D61G/+ mouse lung fibroblasts were characterized by mitochondrial abnormalities, including swollen mitochondria with disrupted electron-lucent cristae and an increased number of autophagosomes compared to wild-type ones. SHP2 D61G/+ MLFs exhibited increased protein levels of autophagy markers, including LC3B-II and p-62, evidence that was confirmed by immunofluorescence analysis. Mitochondrial function analysis revealed that stable (genotype D61G/+) overexpression of SHP2 led to impaired mitochondrial function, as assessed by decreased mitochondrial membrane potential (1.29-fold, p < 0.05), coupling efficiency (1.82 fold, p < 0.05), oxygen consumption rate (1.9-fold, p < 0.05), and increased reactive oxygen species production both at baseline (1.75-fold, p < 0.05) and following H2O2 stimulation (1.63-fold, p < 0.05) compared to wild-type ones (SHP2+/+). SHP2 D61G/+ mouse lung fibroblasts showed enhanced AMPK activity, as well as decreased activation of the mTORC1 signaling pathway, potentially leading to ineffective mitochondrial metabolism and increased autophagy. Conclusions: SHP2 attenuates fibrotic responses in fibroblast cell lines through negative regulation of mitochondrial metabolism and induction of autophagy. SHP2 activation may represent a promising therapeutic strategy for patients with fibrotic lung diseases.

Saracatinib, a Selective Src Kinase Inhibitor, Blocks Fibrotic Responses in Preclinical Models of Pulmonary Fibrosis

Rationale: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and often fatal disorder. Two U.S. Food and Drug Administration-approved antifibrotic drugs, nintedanib and pirfenidone, slow the rate of decline in lung function, but responses are variable and side effects are common. Objectives: Using an in silico data-driven approach, we identified a robust connection between the transcriptomic perturbations in IPF disease and those induced by saracatinib, a selective Src kinase inhibitor originally developed for oncological indications. Based on these observations, we hypothesized that saracatinib would be effective at attenuating pulmonary fibrosis. Methods: We investigated the antifibrotic efficacy of saracatinib relative to nintedanib and pirfenidone in three preclinical models: 1) in vitro in normal human lung fibroblasts; 2) in vivo in bleomycin and recombinant Ad-TGF-β (adenovirus transforming growth factor-β) murine models of pulmonary fibrosis; and 3) ex vivo in mice and human precision-cut lung slices from these two murine models as well as patients with IPF and healthy donors. Measurements and Main Results: In each model, the effectiveness of saracatinib in blocking fibrogenic responses was equal or superior to nintedanib and pirfenidone. Transcriptomic analyses of TGF-β-stimulated normal human lung fibroblasts identified specific gene sets associated with fibrosis, including epithelial-mesenchymal transition, TGF-β, and WNT signaling that was uniquely altered by saracatinib. Transcriptomic analysis of whole-lung extracts from the two animal models of pulmonary fibrosis revealed that saracatinib reverted many fibrogenic pathways, including epithelial-mesenchymal transition, immune responses, and extracellular matrix organization. Amelioration of fibrosis and inflammatory cascades in human precision-cut lung slices confirmed the potential therapeutic efficacy of saracatinib in human lung fibrosis. Conclusions: These studies identify novel Src-dependent fibrogenic pathways and support the study of the therapeutic effectiveness of saracatinib in IPF treatment.

PTPα Promotes Fibroproliferative Responses After Acute Lung Injury

The Acute Respiratory Distress Syndrome (ARDS) is a major healthcare problem, accounting for significant mortality and long-term disability. Approximately 25% of patients with ARDS will develop an over-exuberant fibrotic response, termed fibroproliferative ARDS (FP-ARDS) that portends a poor prognosis and increased mortality. The cellular pathologic processes that drive FP-ARDS remain incompletely understood. We have previously shown that the transmembrane receptor-type tyrosine phosphatase Protein Tyrosine Phosphatase-a (PTPa) promotes pulmonary fibrosis in preclinical murine models through regulation of TGF-b signaling. In this study, we examine the role of PTPa in the pathogenesis of FP-ARDS in a preclinical murine model of acid (HCl)-induced acute lung injury. We demonstrate that while mice genetically deficient in PTPa (Ptpra^-/-) are susceptible to early HCl-induced lung injury, they exhibit markedly attenuated fibroproliferative responses. Additionally, early pro-fibrotic gene expression is reduced in lung tissue after acute lung injury in Ptpra^-/- mice, and stimulation of naïve lung fibroblasts with the BAL fluid from these mice results in attenuated fibrotic outcomes compared to wild type littermate controls. Transcriptomic analyses demonstrates reduced Extracellular Matrix (ECM) deposition and remodeling in mice genetically deficient in PTPa. Importantly, human lung fibroblasts modified with a CRISPR-targeted deletion of PTPRA exhibit reduced expression of profibrotic genes in response to TGF-β stimulation, demonstrating the importance of PTPa in human lung fibroblasts. Together, these findings demonstrate that PTPa is a key regulator of fibroproliferative processes following acute lung injury and could serve as a therapeutic target for patients at risk for poor long-term outcomes in ARDS.

The Prognostic Value of Integrated Analysis of Inflammation and Hypoxia-Related Genes in Idiopathic Pulmonary Fibrosis

Currently, the aetiology and pathogenesis of idiopathic pulmonary fibrosis (IPF) are still largely unclear. Moreover, patients with IPF exhibit a considerable difference in clinical presentation, treatment, and prognosis. Optimal biomarkers or models for IPF prognosis are lacking. Therefore, this study quantified the levels of various hallmarks using a single-sample gene set enrichment analysis algorithm. The hazard ration was calculated using Univariate Cox regression analysis based on the transcriptomic profile of bronchoalveolar lavage cells and clinical survival information. Afterwards, weighted Gene Co-expression Network Analysis was performed to construct a network between gene expression, inflammation response, and hypoxia. Subsequently, univariate Cox, random forest, and multivariate Cox regressions were applied to develop a robust inflammation and hypoxia-related gene signature for predicting clinical outcomes in patients with IPF. Furthermore, a nomogram was constructed to calculate risk assessment. The inflammation response and hypoxia were identified as latent risk factors for patients with IPF. Five genes, including HS3ST1, WFDC2, SPP1, TFPI, and CDC42EP2, were identified that formed the inflammation-hypoxia-related gene signature. Kaplan-Meier plotter showed that the patients with high-risk scores had a worse prognosis than those with low-risk scores in training and validation cohorts. The time-dependent concordance index and the receiver operating characteristic analysis revealed that the risk model could accurately predict the clinical outcome of patients with IPF. Therefore, this study contributes to elucidating the role of inflammation and hypoxia in IPF, which can aid in assessing individual prognosis and personalised treatment decisions.

Endothelial Shp2 deficiency controls alternative activation of macrophage preventing radiation-induced lung injury through Notch signaling

Radiation-induced lung injury is a common late side effect of thoracic radiotherapy. Endothelial dysfunction following leukocytes infiltration is a prominent feature in this process. Here, we established a clinical-mimicking mouse model of radiation-induced lung injury and found the activity of phosphatase Shp2 was elevated in endothelium after injury. Endothelium-specific Shp2 deletion mice showed relieved collagen deposition along with disrupted radiation-induced Jag1 expression in the endothelium. Furthermore, endothelium-derived Jag1 activated the alternative activation of macrophages in vitro and in vivo by paracrine Notch signaling. Consistently, the Notch pathway was significantly activated by chest irradiation in the peripheral blood leukocytes of patients with cancer. Collectively, our work demonstrates that Shp2 participates in the radiation-induced endothelial dysfunction and subsequently inflammatory microenvironment producing during radiation-induced lung injury. Our findings indicate Shp2 as a potential target for radiation-induced lung injury and provide another way for endothelium to participate in the pathological process of radiation-induced lung injury.

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Phosphatase activity of endothelial Shp2 is elevated by irradiation in vitro and in vivo

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Radiation-induced Jag1 is blocked in Shp2-deficient endothelium

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Loss of Shp2 in endothelium relieves radiation-induced pulmonary injury

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Shp2-deficient endothelium restrains macrophage activation via Notch signaling

Antifibrotic effect of Gancao Ganjiang decoction is mediated by PD-1 / TGF-β1 / IL-17A pathway in bleomycin-induced idiopathic pulmonary fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Firstly prescribed in the ancient Chinese book Jingui Yaolue, Gancao Ganjiang decoction (GGD) is a traditional Chinese herbal formula that has been widely used to treat "atrophic lung disease". GGD is a popular and widely used traditional Chinese medicine. The decoction is extracted from the dried rhizomes and roots of Glycyrrhiza uralensis Fisch. and Zingiber officinale Roscoe (2:1).

AIM OF STUDY

To investigate the therapeutic effect of idiopathic pulmonary fibrosis (IPF) of GGD, a bleomycin-induced IPF murine model was used in this study.

MATERIALS AND METHODS

Mice were induced by bleomycin instillation and GGD was orally administered. Changes on mice weight were recorded during the experiment. Lung weight was recorded on days 14 and 28, and pulmonary index was calculated accordingly. Pathological evaluation, including fibrosis analysis of lung tissue, was assessed by H&E and Masson staining. The expression of PD-1, p-STAT3 and IL-17A were detected by immunohistochemistry (IHC). The expression of p-STAT3 in lung tissues of mice were detected by Western blot. The level of IL-17A in lung tissue were detected by ELISA. The expression of PD-1 in CD4+ T cells in peripheral blood of mice was detected by flow cytometry. The levels of hydroxyproline and TGF-β1 in lung tissue were detected by ELISA. The expression of E-cadherin, vimentin and α-SMA in lung tissues of mice were detected by qRT-PCR and Western blot.

RESULTS

GGD can increase body weight and reduce pulmonary index in mice with pulmonary fibrosis. As such, GGD can significantly improve the inflammatory and alleviate IPF in the lung tissue of mice. GGD treatment was capable of reducing the content of PD-1 in lung tissue as well as the expression of PD-1 in CD4+ T cells in peripheral blood. Likewise, GGD was able to reduce the content of p-STAT3, IL-17A and TGF-β1. In addition, GGD stimulation could inhibit epithelial-mesenchymal transformation (EMT) by increasing the expression of E-cadherin and reducing vimentin and α-SMA, thus reducing extracellular matrix (ECM) deposition.

CONCLUSION

Our results indicate that GGD positively affects IPF by regulating PD-1/TGF-β1/IL-17A pathway.

SHP2: The protein tyrosine phosphatase involved in chronic pulmonary inflammation and fibrosis

Chronic respiratory diseases (CRDs), including pulmonary fibrosis, chronic obstructive pulmonary disease (COPD), lung cancer, and asthma, are significant global health problems due to their prevalence and rising incidence. The roles of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) in controlling tyrosine phosphorylation of targeting proteins modulate multiple physiological cellular responses and contribute to the pathogenesis of CRDs. Src homology-2 domain-containing PTP2 (SHP2) plays a pivotal role in modulating downstream growth factor receptor signaling and cytoplasmic PTKs, including MAPK/ERK, PI3K/AKT, and JAK/STAT pathways, to regulate cell survival and proliferation. In addition, SHP2 mutation and activation are commonly implicated in tumorigenesis. However, little is known about SHP2 in chronic pulmonary inflammation and fibrosis. This review discusses the potential involvement of SHP2 deregulation in chronic pulmonary inflammation and fibrosis, as well as the therapeutic effects of targeting SHP2 in CRDs.

CD148 Deficiency in Fibroblasts Promotes the Development of Pulmonary Fibrosis

Rationale: CD148/PTRJ (receptor-like protein tyrosine phosphatase η) exerts antifibrotic effects in experimental pulmonary fibrosis via interactions with its ligand syndecan-2; however, the role of CD148 in human pulmonary fibrosis remains incompletely characterized.Objectives: We investigated the role of CD148 in the profibrotic phenotype of fibroblasts in idiopathic pulmonary fibrosis (IPF).Methods: Conditional CD148 fibroblast-specific knockout mice were generated and exposed to bleomycin and then assessed for pulmonary fibrosis. Lung fibroblasts (mouse lung and human IPF lung), and precision-cut lung slices from human patients with IPF were isolated and subjected to experimental treatments. A CD148-activating 18-aa mimetic peptide (SDC2-pep) derived from syndecan-2 was evaluated for its therapeutic potential.Measurements and Main Results: CD148 expression was downregulated in IPF lungs and fibroblasts. In human IPF lung fibroblasts, silencing of CD148 increased extracellular matrix production and resistance to apoptosis, whereas overexpression of CD148 reversed the profibrotic phenotype. CD148 fibroblast-specific knockout mice displayed increased pulmonary fibrosis after bleomycin challenge compared with control mice. CD148-deficient fibroblasts exhibited hyperactivated PI3K/Akt/mTOR signaling, reduced autophagy, and increased p62 accumulation, which induced NF-κB activation and profibrotic gene expression. SDC2-pep reduced pulmonary fibrosis in vivo and inhibited IPF-derived fibroblast activation. In precision-cut lung slices from patients with IPF and control patients, SDC2-pep attenuated profibrotic gene expression in IPF and normal lungs stimulated with profibrotic stimuli.Conclusions: Lung fibroblast CD148 activation reduces p62 accumulation, which exerts antifibrotic effects by inhibiting NF-κB-mediated profibrotic gene expression. Targeting the CD148 phosphatase with activating ligands such as SDC2-pep may represent a potential therapeutic strategy in IPF.

Long noncoding RNA TINCR is a novel regulator of human bronchial epithelial cell differentiation state

Long-noncoding RNAs (lncRNAs) have numerous biological functions controlling cell differentiation and tissue development. The knowledge about the role of lncRNAs in human lungs remains limited. Here we found the regulatory role of the terminal differentiation-induced lncRNA (TINCR) in bronchial cell differentiation. RNA in situ hybridization revealed that TINCR was mainly expressed in bronchial epithelial cells in normal human lung. We performed RNA sequencing analysis of normal human bronchial epithelial cells (NHBECs) with or without TINCR inhibition and found the differential expression of 603 genes, which were enriched for cell adhesion and migration, wound healing, extracellular matrix organization, tissue development and differentiation. To investigate the role of TINCR in the differentiation of NHBECs, we employed air-liquid interface culture and 3D organoid formation assay. TINCR was upregulated during differentiation, loss of TINCR significantly induced an early basal-like cell phenotype (TP63) and a ciliated cell differentiation (FOXJ1) in late phase and TINCR overexpression suppressed basal cell phenotype and the differentiation toward to ciliated cells. Critical regulators of differentiation such as SOX2 and NOTCH genes (NOTCH1, HES1, and JAG1) were significantly upregulated by TINCR inhibition and downregulated by TINCR overexpression. RNA immunoprecipitation assay revealed that TINCR was required for the direct bindings of Staufen1 protein to SOX2, HES1, and JAG1 mRNA. Loss of Staufen1 induced TP63, SOX2, NOTCH1, HES1, and JAG1 mRNA expressions, which TINCR overexpression suppressed partially. In conclusion, TINCR is a novel regular of bronchial cell differentiation, affecting downstream regulators such as SOX2 and NOTCH genes, potentially in coordination with Staufen1.

Overcoming interferon (IFN)-γ resistance ameliorates transforming growth factor (TGF)-β-mediated lung fibroblast-to-myofibroblast transition and bleomycin-induced pulmonary fibrosis

Abnormal activation of transforming growth factor (TGF)-β is a common cause of fibroblast activation and fibrosis. In bleomycin (BLM)-induced lung fibrosis, the marked expression of phospho-Src homology-2 domain-containing phosphatase (SHP) 2, phospho-signal transducer and activator of transcription (STAT) 3, and suppressor of cytokine signaling (SOCS) 3 was highly associated with pulmonary parenchymal lesions and collagen deposition. Human pulmonary fibroblasts differentiated into myofibroblasts exhibited activation of SHP2, SOCS3, protein inhibitor of activated STAT1, STAT3, interleukin (IL)-6, and IL-10. The significant retardation of interferon (IFN)-γ signaling in myofibroblasts was revealed by the decreased expression of phospho-STAT1, IFN-γ-associated genes, and IFN-γ-inducible protein (IP) 10. Microarray analysis showed an induction of fibrotic genes in TGF-β1-differentiated myofibroblasts, whereas IFN-γ-regulated anti-fibrotic genes were suppressed. Interestingly, BIBF 1120 treatment effectively inhibited both STAT3 and SHP2 phosphorylation in TGF-β1-differentiated myofibroblasts and BLM fibrotic lung tissues, which was accompanied by suppression of fibroblast-myofibroblast transition. Moreover, the combined treatment of BIBF 1120 plus IFN-γ or SHP2 inhibitor PHPS1 plus IFN-γ markedly reduced TGF-β1-induced α-smooth muscle actin and further ameliorated BLM lung fibrosis. Accordingly, myofibroblasts were hyporesponsiveness to IFN-γ, while blockade of SHP2 contributed to the anti-fibrotic efficacy of IFN-γ.

Protein tyrosine phosphatase-α amplifies transforming growth factor-β-dependent profibrotic signaling in lung fibroblasts

Idiopathic pulmonary fibrosis (IPF) is a progressive, often fatal, fibrosing lung disease for which treatment remains suboptimal. Fibrogenic cytokines, including transforming growth factor-β (TGF-β), are central to its pathogenesis. Protein tyrosine phosphatase-α (PTPα) has emerged as a key regulator of fibrogenic signaling in fibroblasts. We have reported that mice globally deficient in PTPα (Ptpra-/-) were protected from experimental pulmonary fibrosis, in part via alterations in TGF-β signaling. The goal of this study was to determine the lung cell types and mechanisms by which PTPα controls fibrogenic pathways and whether these pathways are relevant to human disease. Immunohistochemical analysis of lungs from patients with IPF revealed that PTPα was highly expressed by mesenchymal cells in fibroblastic foci and by airway and alveolar epithelial cells. To determine whether PTPα promotes profibrotic signaling pathways in lung fibroblasts and/or epithelial cells, we generated mice with conditional (floxed) Ptpra alleles (Ptpraf/f). These mice were crossed with Dermo1-Cre or with Sftpc-CreERT2 mice to delete Ptpra in mesenchymal cells and alveolar type II cells, respectively. Dermo1-Cre/Ptpraf/f mice were protected from bleomycin-induced pulmonary fibrosis, whereas Sftpc-CreERT2/Ptpraf/f mice developed pulmonary fibrosis equivalent to controls. Both canonical and noncanonical TGF-β signaling and downstream TGF-β-induced fibrogenic responses were attenuated in isolated Ptpra-/- compared with wild-type fibroblasts. Furthermore, TGF-β-induced tyrosine phosphorylation of TGF-β type II receptor and of PTPα were attenuated in Ptpra-/- compared with wild-type fibroblasts. The phenotype of cells genetically deficient in PTPα was recapitulated with the use of a Src inhibitor. These findings suggest that PTPα amplifies profibrotic TGF-β-dependent pathway signaling in lung fibroblasts.

Inhibition of bleomycin-induced pulmonary fibrosis in mice by the novel peptide EZY-1 purified from Eucheuma

For the first time, a new 16-amino-acid peptide was isolated from Eucheuma, an edible seaweed, and named EZY-1. EZY-1 was used to interfere with bleomycin-induced mice pulmonary fibrosis. The target proteins of EZY-1 were screened by an in vitro pull-down method combined with LC-MS/MS. The results showed that EZY-1 can inhibit the idiopathic pulmonary fibrosis (IPF) induced by bleomycin. The potency and safety of EZY-1 are superior to those of the drug used for clinical treatment, pirfenidone. The results showed that EZY-1 suppresses the TGF-β/Smad, PI3K-Akt-mTOR, Rac1-PAK2-cAb1 and MAPK signal transduction pathways. Proteins such as ERK, Akt, PDGF receptor β, vitronectin, raptor and SHP2 exhibited binding to EZY-1 in an in vitro pull-down assay combined with LC-MS/MS analysis. EZY-1 was confirmed to be an effective component of Eucheuma in the inhibition of IPF. The signalling pathways and target proteins of EZY-1 were preliminarily predicted. This study lays the foundation for the development of new drugs from Eucheuma for the treatment of IPF.

PD-1 up-regulation on CD4+ T cells promotes pulmonary fibrosis through STAT3-mediated IL-17A and TGF-β1 production

Pulmonary fibrosis is a progressive inflammatory disease with high mortality and limited therapeutic options. Previous genetic and immunologic investigations suggest common intersections between idiopathic pulmonary fibrosis (IPF), sarcoidosis, and murine models of pulmonary fibrosis. To identify immune responses that precede collagen deposition, we conducted molecular, immunohistochemical, and flow cytometric analysis of human and murine specimens. Immunohistochemistry revealed programmed cell death-1 (PD-1) up-regulation on IPF lymphocytes. PD-1⁺CD4⁺ T cells with reduced proliferative capacity and increased transforming growth factor-β (TGF-β)/interleukin-17A (IL-17A) expression were detected in IPF, sarcoidosis, and bleomycin CD4⁺ T cells. PD-1⁺ T helper 17 cells are the predominant CD4⁺ T cell subset expressing TGF-β. Coculture of PD-1⁺CD4⁺ T cells with human lung fibroblasts induced collagen-1 production. Strikingly, ex vivo PD-1 pathway blockade resulted in reductions in TGF-β and IL-17A expression from CD4⁺ T cells, with concomitant declines in collagen-1 production from fibroblasts. Molecular analysis demonstrated PD-1 regulation of the transcription factor STAT3 (signal transducer and activator of transcription 3). Chemical blockade of STAT3, using the inhibitor STATTIC, inhibited collagen-1 production. Both bleomycin administration to PD-1 null mice or use of antibody against programmed cell death ligand 1 (PD-L1) demonstrated significantly reduced fibrosis compared to controls. This work identifies a critical, previously unrecognized role for PD-1⁺CD4⁺ T cells in pulmonary fibrosis, supporting the use of readily available therapeutics that directly address interstitial lung disease pathophysiology.

Role of dual-specificity protein phosphatase DUSP10/MKP-5 in pulmonary fibrosis

Mitogen-activated protein kinase (MAPK) phosphatase 5 (MKP-5) is a member of the dual-specificity family of protein tyrosine phosphatases that negatively regulates p38 MAPK and the JNK. MKP-5-deficient mice exhibit improved muscle repair and reduced fibrosis in an animal model of muscular dystrophy. Here, we asked whether the effects of MKP-5 on muscle fibrosis extend to other tissues. Using a bleomycin-induced model of pulmonary fibrosis, we found that MKP-5-deficient mice were protected from the development of lung fibrosis, expressed reduced levels of hydroxyproline and fibrogenic genes, and displayed marked polarization towards an M1-macrophage phenotype. We showed that the profibrogenic effects of the transforming growth factor-β1 (TGF-β1) were inhibited in MKP-5-deficient lung fibroblasts. MKP-5-deficient fibroblasts exhibited enhanced p38 MAPK activity, impaired Smad3 phosphorylation, increased Smad7 levels, and decreased expression of fibrogenic genes. Myofibroblast differentiation was attenuated in MKP-5-deficient fibroblasts. Finally, we found that MKP-5 expression was increased in idiopathic pulmonary fibrosis (IPF)-derived lung fibroblasts but not in whole IPF lungs. These data suggest that MKP-5 plays an essential role in promoting lung fibrosis. Our results couple MKP-5 with the TGF-β1 signaling machinery and imply that MKP-5 inhibition may serve as a therapeutic target for human lung fibrosis.

Impact of Cigarette Smoke Exposure on the Lung Fibroblastic Response after Influenza Pneumonia

Influenza viruses can result in significant lung injury with significant morbidity and mortality. In this study, we evaluated the impact of cigarette smoke (CS) exposure on the pulmonary fibroblastic response after influenza infection. We used a murine model in which animals were exposed to CS or room air and subsequently infected with H1N1 influenza virus. Inflammatory and fibrotic responses were measured at different time points after influenza infection. Primary fibroblasts were isolated from the lungs of mice and their characteristics were evaluated. Exposure to CS significantly increased the amount of collagen in the lungs of mice infected with influenza virus compared with the nonsmoking group at 30 days after infection. Furthermore, the presence of fibroblast-specific protein-positive cells increased in the lungs of influenza-infected mice that were exposed to CS compared with the infection-alone group. The smoking group also showed delays in weight recovery and higher cell counts in BAL fluid after infection. Active transforming growth factor β1 levels in BAL fluid increased in both groups; however, CS-exposed mice had a later surge in active transforming growth factor β1 (Day 24). Ex vivo cultures of lung-derived fibroblasts from CS-exposed mice with influenza infection showed rapid proliferation, increased expression of α-smooth muscle actin-stained stress fibers, and higher expression of growth factors compared with fibroblasts from room air-exposed lungs after infection. These results suggest that CS exposure changes the fibroblastic potential, leading to increased fibrosis after influenza infection.

Ability to Suppress TGF-β-Activated Myofibroblast Differentiation Distinguishes the Anti-pulmonary Fibrosis Efficacy of Two Danshen-Containing Chinese Herbal Medicine Prescriptions

Background: Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease with limited treatment options. It also leads to progressive respiratory failure, which subsequently affects the heart functionality, a pathological heart-lung interaction increasingly noticed and defined as pulmonary-heart disease (PHD). Traditional Chinese medicine (TCM) theory for treating “phlegm-stasis cementation syndrome” may suggest a possibility of treating PHD complication with Chinese medicine prescriptions previously used for cardiovascular diseases.

Methods: Here, we evaluate the efficacies of two compound Chinese medicine prescriptions, Danlou prescription (DLP) and Danhong prescription (DHP), which share a common herbal component, Salvia miltiorrhiza (Danshen), on pulmonary fibrosis. Severity grades of Bleomycin (BLM)-induced pulmonary fibrosis were assessed by micro-Computerized Tomography (μCT) in accordance with the clinical evaluation standard. Lung pathological changes and collagen deposition were investigated by histopathology. Myofibroblast differentiation was assessed by immunohistochemistry of α-SMA and TGF-β receptor type II expression in situ. Network pharmacology analysis of the drug-target interaction in IPF progression for DLP or DHP was performed using Ingenuity^® Pathways Analysis (IPA) system.

Results: We show that a non-invasive μCT effectively monitor and quantify BLM-induced pulmonary fibrosis and its treatment efficacy by Chinese medicine prescription in rodents. In addition, although both containing Salvia miltiorrhiza, DLP but not DHP mitigates BLM-induced lung fibrosis by inhibiting the TGF-β signaling-activated myofibroblast differentiation and α-SMA expression in a mouse model. Core analysis by IPA revealed that DLP ingredients regulated not only pulmonary fibrosis related inflammatory genes but also genes associated with myofibroblast activation and collagen deposition.

Conclusion: This study suggests that a clinically efficacious cardiovascular Chinese herbal medicine (DLP) can be successfully repurposed to treat a lung disease in pulmonary fibrosis guided by TCM theory. Our comparative study between DLP and DHP demonstrated a critical requirement of suppressing both pro-inflammatory and pro-fibrotic pathways for the treatment of pulmonary fibrosis, supporting that a multi-component prescription capable of “removing both phlegm and blood stasis” will better achieve co-protection of heart and lung in PHD.

Biologic Treatments in Interstitial Lung Diseases

Interstitial lung diseases (ILD) represent a group of heterogeneous parenchymal lung disorders with complex pathophysiology, characterized by different clinical and radiological patterns, ultimately leading to pulmonary fibrosis. A considerable proportion of these disease entities present with no effective treatment, as current therapeutic regimens only slow down disease progression, thus leaving patients, at best case, with considerable functional disability. Biologic therapies have emerged and are being investigated in patients with different forms of ILD. Unfortunately, their safety profile has raised many concerns, as evidence shows that they might cause or exacerbate ILD status in a subgroup of patients. This review article aims to summarize the current state of knowledge on their role in patients with ILD and highlight future perspectives.

Loss of myeloid-specific protein phosphatase 2A enhances lung injury and fibrosis and results in IL-10-dependent sensitization of epithelial cell apoptosis

Protein phosphatase 2A (PP2A), a ubiquitously expressed Ser/Thr phosphatase is an important regulator of cytokine signaling and cell function. We previously showed that myeloid-specific deletion of PP2A (LysM^crePP2A^-/-) increased mortality in a murine peritoneal sepsis model. In the current study, we assessed the role of myeloid PP2A in regulation of lung injury induced by lipopolysaccharide (LPS) or bleomycin delivered intratracheally. LysM^crePP2A^-/- mice experienced increased lung injury in response to both LPS and bleomycin. LysM^crePP2A^-/- mice developed more exuberant fibrosis in response to bleomycin, elevated cytokine responses, and chronic myeloid inflammation. Bone marrow-derived macrophages (BMDMs) from LysM^crePP2A^-/- mice showed exaggerated inflammatory cytokine release under conditions of both M1 and M2 activation. Notably, secretion of IL-10 was elevated under all stimulation conditions, including activation of BMDMs by multiple Toll-like receptor ligands. Supernatants collected from LPS-stimulated LysM^crePP2A^-/- BMDMs induced epithelial cell apoptosis in vitro but this effect was mitigated when IL-10 was also depleted from the BMDMs by crossing LysM^crePP2A^-/- mice with systemic IL-10^-/- mice (LysM^crePP2A^-/- × IL-10^-/-) or when IL-10 was neutralized. Despite these findings, IL-10 did not directly induce epithelial cell apoptosis but sensitized epithelial cells to other mediators from the BMDMs. Taken together our results demonstrate that myeloid PP2A regulates production of multiple cytokines but that its effect is most pronounced on IL-10 production. Furthermore, IL-10 sensitizes epithelial cells to apoptosis in response to myeloid-derived mediators, which likely contributes to the pathogenesis of lung injury and fibrosis in this model.

The Importance of Tyrosine Phosphorylation Control of Cellular Signaling Pathways in Respiratory Disease: pY and pY Not

Reversible phosphorylation of proteins on tyrosine residues is an essential signaling mechanism by which diverse cellular processes are closely regulated. The tight temporal and spatial control of the tyrosine phosphorylation status of proteins by protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) is critical to cellular homeostasis as well as to adaptations to the external environment. Via regulation of cellular signaling cascades involving other protein kinases and phosphatases, receptors, adaptor proteins, and transcription factors, PTKs and PTPs closely control diverse cellular processes such as proliferation, differentiation, migration, inflammation, and maintenance of cellular barrier function. Given these key regulatory roles, it is not surprising that dysfunction of PTKs and PTPs is important in the pathogenesis of human disease, including many pulmonary diseases. The roles of various PTKs and PTPs in acute lung injury and repair, pulmonary fibrosis, pulmonary vascular disease, and inflammatory airway disease are discussed in this review. It is important to note that although there is overlap among many of these proteins in various disease states, the mechanisms by which they influence the pathogenesis of these conditions differ, suggesting wide-ranging roles for these enzymes and their potential as therapeutic targets.

Potential regulatory role of circular RNA in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive type of interstitial pneumonia with unknown causes, poor prognosis and no effective therapy available. Circular RNAs (circRNAs), which serve as potential therapeutic targets and diagnostic biomarkers for certain diseases, represent a recent hotspot in the field of RNA research. In the present study, a total of 67 significantly dysregulated circRNAs were identified in the plasma of IPF patients by using a circRNA microarray. Among these circRNAs, 38 were upregulated, whereas 29 were downregulated. Further validation of the results by polymerase chain reaction analysis indicated that Homo sapiens (hsa)_circRNA_100906, hsa_circRNA_102100 and hsa_circRNA_102348 were significantly upregulated, whereas hsa_circRNA_101225, hsa_circRNA_104780 and hsa_circRNA_101242 were downregulated in plasma samples of IPF patients compared with those in samples from healthy controls. The majority of differentially expressed circRNAs were generated from exonic regions. The host genes of the differentially expressed circRNAs were involved in the regulation of the cell cycle, adherens junctions and RNA transport. The competing endogenous RNA (ceRNA) network of the circRNAs/micro(mi)RNAs/mRNAs indicated that circRNA-protected mRNA participated in transforming growth factor-β1, hypoxia-inducible factor-1, Wnt, Janus kinase, Rho-associated protein kinase, vascular endothelial growth factor, mitogen-activated protein kinase, Hedgehog and nuclear factor κB signalling pathways or functioned as biomarkers for pulmonary fibrosis. Furthermore, luciferase reporter assays confirmed that hsa_circRNA_100906 and hsa_circRNA_102348 directly interact with miR-324-5p and miR-630, respectively, which were downregulated in IPF patients. The present study provided a novel avenue for exploring the underlying molecular mechanisms of IPF disease.

Novel management strategies for idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) treatment was revolutionized by the advent of two novel antifibrotics, nintedanib and pirfenidone. However, neither is a panacea and other agents are still sorely needed. This review presents on-going efforts to improve outcomes for patients with IPF by targeting novel pharmacologic pathways, improving comorbidity management, and aiming for improved quality of life. Areas covered: We provide an overview of on-going basic and clinical science efforts focused on development of additional drug therapies for patients with IPF. Known and emerging pathogenic pathways such as the microbiome and pulmonary vasculature hold promise as targets for therapy. While the focus remains on pharmacologic intervention, the impact of comorbidities and their management may also impact patient outcomes significantly. Supportive care with pulmonary rehabilitation, oxygen therapy, and palliative care remain integral at various stages of the disease course. Finally, lung transplant is the only lifesaving intervention for patients with end-stage fibrosis. Expert commentary: Future investigation should aim to prevent the initial insult or injury that engages the multiple pathways associated with the development and progression of IPF. Targeted therapies represent just one management aspect with a multidisciplinary approach necessary for the global holistic care of these complex patients.

The tyrosine phosphatase SHP2 controls TGFβ-induced STAT3 signaling to regulate fibroblast activation and fibrosis

Uncontrolled activation of TGFβ signaling is a common denominator of fibrotic tissue remodeling. Here we characterize the tyrosine phosphatase SHP2 as a molecular checkpoint for TGFβ-induced JAK2/STAT3 signaling and as a potential target for the treatment of fibrosis. TGFβ stimulates the phosphatase activity of SHP2, although this effect is in part counterbalanced by inhibitory effects on SHP2 expression. Stimulation with TGFβ promotes recruitment of SHP2 to JAK2 in fibroblasts with subsequent dephosphorylation of JAK2 at Y570 and activation of STAT3. The effects of SHP2 on STAT3 activation translate into major regulatory effects of SHP2 on fibroblast activation and tissue fibrosis. Genetic or pharmacologic inactivation of SHP2 promotes accumulation of JAK2 phosphorylated at Y570, reduces JAK2/STAT3 signaling, inhibits TGFβ-induced fibroblast activation and ameliorates dermal and pulmonary fibrosis. Given the availability of potent SHP2 inhibitors, SHP2 might thus be a potential target for the treatment of fibrosis.

SHP2 protects endothelial cell barrier through suppressing VE-cadherin internalization regulated by MET-ARF1

Vascular endothelial (VE)-cadherin junctional localization is known to play a central role in vascular development, endothelial barrier integrity, and homeostasis. The sarcoma homology domain containing protein tyrosine phosphatase (SHP)2 has been shown to be involved in regulating endothelial barrier function; however, the mechanisms remain largely unknown. In this work SHP2 knockdown in an HUVEC monolayer increased VE-cadherin internalization and endothelial barrier permeability. Loss of SHP2 specifically augmented the GTPase activity of ADP-ribosylation factor (ARF)-1. ARF1 knockdown or inhibition of its guanine nucleotide exchange factors (GEFs) markedly attenuated VE-cadherin internalization and barrier hyperpermeability induced by SHP2 deficiency. SHP2 knockdown increased the total and phosphorylated levels of MET, whose activity was necessary for ARF1 activation and VE-cadherin internalization. Furthermore, constitutive endothelium-specific deletion of Shp2 in mice led to disrupted endothelial cell junctions, massive hemorrhage, and lethality in embryos. Induced and endothelium-specific deletion of Shp2 in adult mice resulted in lung hyperpermeability. Inhibitors for ARF1-GEF or MET used in pregnant mice prevented the vascular leakage in endothelial Shp2-deleted embryos. Together, our findings define a novel role of SHP2 in stabilizing junctional VE-cadherin in the resting endothelial barrier through suppressing MET and ARF1 activation.-Zhang, J., Huang, J., Qi, T., Huang, Y., Lu, Y., Zhan, T., Gong, H., Zhu, Z., Shi, Y., Zhou, J., Yu, L., Zhang, X., Cheng, H., Ke, Y. SHP2 protects endothelial cell barrier through suppressing VE-cadherin internalization regulated by MET-ARF1.

Mesenchymal Stem Cells for the Treatment of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is an inexorably progressive lung disease of unknown origin. Prognosis is poor, with limited treatment options available, and the median survival remains just 3-5 years. Despite the use of pirfenidone and nintedanib for the treatment of IPF, curative therapies remain elusive and mortality remains high. Regenerative medicine and the use of cell-based therapies has recently emerged as a potential option for various diseases. Promising results of preclinical studies using mesenchymal stem cells (MSCs) suggest that they may represent a potential therapeutic option for the treatment of chronic lung diseases including IPF. Encouraging results of Phase 1 studies of MSCs various have reduced safety concerns. Nonetheless, there is still a pressing need for exploratory biomarkers and interval end-points in the context of MSCs investigation. This review intends to summarize the current state of knowledge for stem cells in the experimental and clinical setting of IPF, present important safety and efficacy issues, highlight future challenges and address the need for large, multicenter clinical trials coupled with realistic end-points, including biomarkers, to assess treatment efficacy.

Impact of Transcriptomics on Our Understanding of Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a lethal fibrotic lung disease characterized by aberrant remodeling of the lung parenchyma with extensive changes to the phenotypes of all lung resident cells. The introduction of transcriptomics, genome scale profiling of thousands of RNA transcripts, caused a significant inversion in IPF research. Instead of generating hypotheses based on animal models of disease, or biological plausibility, with limited validation in humans, investigators were able to generate hypotheses based on unbiased molecular analysis of human samples and then use animal models of disease to test their hypotheses. In this review, we describe the insights made from transcriptomic analysis of human IPF samples. We describe how transcriptomic studies led to identification of novel genes and pathways involved in the human IPF lung such as: matrix metalloproteinases, WNT pathway, epithelial genes, role of microRNAs among others, as well as conceptual insights such as the involvement of developmental pathways and deep shifts in epithelial and fibroblast phenotypes. The impact of lung and transcriptomic studies on disease classification, endotype discovery, and reproducible biomarkers is also described in detail. Despite these impressive achievements, the impact of transcriptomic studies has been limited because they analyzed bulk tissue and did not address the cellular and spatial heterogeneity of the IPF lung. We discuss new emerging technologies and applications, such as single-cell RNAseq and microenvironment analysis that may address cellular and spatial heterogeneity. We end by making the point that most current tissue collections and resources are not amenable to analysis using the novel technologies. To take advantage of the new opportunities, we need new efforts of sample collections, this time focused on access to all the microenvironments and cells in the IPF lung.

Pulmonary hypertension in patients with interstitial lung disease

Interstitial lung diseases (ILDs) comprise a broad and heterogeneous group of more than two hundred diseases with common functional characteristics. Their diagnosis and management require a multidisciplinary approach. This multidisciplinary approach involves the assessment of comorbid conditions including pulmonary hypertension (PH) that exerts a dramatic impact on survival. The current World Health Organization (WHO) classification of PH encompasses many of the interstitial lung diseases into WHO Group 3, while sarcoidosis, Pulmonary Langerhans Cell Histiocytosis and lymphangioleiomyomatosis are placed into WHO Group 5 as diseases with unclear or multifactorial mechanisms. Connective tissue diseases could span any of the 5 WHO groups based on the primary phenotype into which they manifest. Interestingly, several challenging phenotypes present with features that overlap between two or more WHO PH groups. Currently, PH-specific treatment is recommended only for patients classified into WHO Group 1 PH. The lack of specific treatment for other groups, including PH in the setting of ILD, reflects the poor outcomes of these patients. Thus, identification of the optimal strategy for ILD patients with PH remains an amenable need. This review article provides a brief overview of biomarkers indicative of vascular remodeling in interstitial lung disease, summarizes the current state of knowledge regarding patients with PH and ILD and highlights future perspectives that remain to be addressed.

Fibrosis: Lessons from OMICS analyses of the human lung

In recent decades there has been a significant shift in our understanding of idiopathic pulmonary fibrosis (IPF), a progressive and lethal disorder. While initially much of the mechanistic understanding was derived from hypotheses generated from animal models of disease, in recent decades new insights derived from humans with IPF have taken precedence. This is mainly because of the establishment of large collections of IPF lung tissues and patient cohorts, and the emergence of high throughput profiling technologies collectively termed 'omics' technologies based on their shared suffix. In this review we describe impacts of 'omics' analyses of human IPF samples on our understanding of the disease. In particular, we discuss the results of genomics and transcriptomics studies, as well as proteomics, epigenomics and metabolomics. We then describe how these findings can be integrated in a modified paradigm of human idiopathic pulmonary fibrosis, that introduces the 'hallmarks of aging' as a central theme in the IPF lung. This allows resolution of all the disparate cellular and molecular features in IPF, from the central role of epithelial cells, through the dramatic phenotypic alterations observed in fibroblasts and the numerous aberrations that inflammatory cells exhibit. We end with reiterating a call for renewed efforts to collect and analyze carefully characterized human tissues, in ways that would facilitate implementation of novel technologies for high resolution single cell omics profiling.

Safety and efficacy of nintedanib in idiopathic pulmonary fibrosis: A real-life observational study in Greece

BACKGROUND

Nintedanib represents an antifibrotic compound able to slow down disease progression of patients with idiopathic pulmonary fibrosis (IPF).

OBJECTIVE

To investigate the safety and efficacy of nintedanib in patients with IPF in a real-life setting.

METHODS

This was a multicentre, retrospective, observational, real-life study for patients with IPF receiving nintedanib between October 2014 and October 2016.

RESULTS

We identified 94 patients with IPF receiving nintedanib (72 males, mean age±SD: 73.8 ± 7.5, mean%FVC±SD = 68.1 ± 18.3, mean%DLCo±SD = 44.4 ± 14.5). Diarrhea (n = 52, 55.3%) was the most commonly reported adverse event. Twenty patients (21.2%) had to permanently discontinue nintedanib due to severe adverse events. In the 6-months follow-up, median decline in %FVC predicted and %DLCO predicted were 1.36 (95%Cl: 0 to 2.97) and 4.00 (95%Cl: 2.01 to 6.20), respectively, when deaths were censored and excluded from the analysis. At 12 months, mean%FVC±SD and mean%DLCo±SD were 64.5 ± 19.1 and 43.7 ± 15.4, respectively. With regards to mortality, 17 patients (18.1%) died over a study period of 730 days.

CONCLUSION

Nintedanib demonstrated an acceptable safety and efficacy profile in our real-world observational study. Prospective observational studies in the context of registries that collect well-defined supporting data over time are sorely needed to answer residual questions on drug's performance.

Thyroid hormone inhibits lung fibrosis in mice by improving epithelial mitochondrial function

Thyroid hormone (TH) is critical for the maintenance of cellular homeostasis during stress responses, but its role in lung fibrosis is unknown. Here we found that the activity and expression of iodothyronine deiodinase 2 (DIO2), an enzyme that activates TH, were higher in lungs from patients with idiopathic pulmonary fibrosis than in control individuals and were correlated with disease severity. We also found that Dio2-knockout mice exhibited enhanced bleomycin-induced lung fibrosis. Aerosolized TH delivery increased survival and resolved fibrosis in two models of pulmonary fibrosis in mice (intratracheal bleomycin and inducible TGF-β1). Sobetirome, a TH mimetic, also blunted bleomycin-induced lung fibrosis. After bleomycin-induced injury, TH promoted mitochondrial biogenesis, improved mitochondrial bioenergetics and attenuated mitochondria-regulated apoptosis in alveolar epithelial cells both in vivo and in vitro. TH did not blunt fibrosis in Ppargc1a- or Pink1-knockout mice, suggesting dependence on these pathways. We conclude that the antifibrotic properties of TH are associated with protection of alveolar epithelial cells and restoration of mitochondrial function and that TH may thus represent a potential therapy for pulmonary fibrosis.

Protein Tyrosine Phosphatases in Systemic Sclerosis: Potential Pathogenic Players and Therapeutic Targets

PURPOSE OF REVIEW

The pathogenesis of systemic sclerosis depends on a complex interplay between autoimmunity, vasculopathy, and fibrosis. Reversible phosphorylation on tyrosine residues, in response to growth factors and other stimuli, critically regulates each one of these three key pathogenic processes. Protein tyrosine kinases, the enzymes that catalyze addition of phosphate to tyrosine residues, are known players in systemic sclerosis, and tyrosine kinase inhibitors are undergoing clinical trials for treatment of this disease. Until recently, the role of tyrosine phosphatases-the enzymes that counteract the action of tyrosine kinases by removing phosphate from tyrosine residues-in systemic sclerosis has remained largely unknown. Here, we review the function of tyrosine phosphatases in pathways relevant to the pathogenesis of systemic sclerosis and their potential promise as therapeutic targets to halt progression of this debilitating rheumatic disease.

RECENT FINDINGS

Protein tyrosine phosphatases are emerging as important regulators of a multitude of signaling pathways and undergoing validation as molecular targets for cancer and other common diseases. Recent advances in drug discovery are paving the ways to develop new classes of tyrosine phosphatase modulators to treat human diseases. Although so far only few reports have focused on tyrosine phosphatases in systemic sclerosis, these enzymes play a role in multiple pathways relevant to disease pathogenesis. Further studies in this field are warranted to explore the potential of tyrosine phosphatases as drug targets for systemic sclerosis.

Exploring Animal Models That Resemble Idiopathic Pulmonary Fibrosis

Large multicenter clinical trials have led to two recently approved drugs for patients with idiopathic pulmonary fibrosis (IPF); yet, both of these therapies only slow disease progression and do not provide a definitive cure. Traditionally, preclinical trials have utilized mouse models of bleomycin (BLM)-induced pulmonary fibrosis—though several limitations prevent direct translation to human IPF. Spontaneous pulmonary fibrosis occurs in other animal species, including dogs, horses, donkeys, and cats. While the fibrotic lungs of these animals share many characteristics with lungs of patients with IPF, current veterinary classifications of fibrotic lung disease are not entirely equivalent. Additional studies that profile these examples of spontaneous fibroses in animals for similarities to human IPF should prove useful for both human and animal investigators. In the meantime, studies of BLM-induced fibrosis in aged male mice remain the most clinically relevant model for preclinical study for human IPF. Addressing issues such as time course of treatment, animal size and characteristics, clinically irrelevant treatment endpoints, and reproducibility of therapeutic outcomes will improve the current status of preclinical studies. Elucidating the mechanisms responsible for the development of fibrosis and disrepair associated with aging through a collaborative approach between researchers will promote the development of models that more accurately represent the realm of interstitial lung diseases in humans.

Bioinformatics methods for identifying differentially expressed genes and signaling pathways in nano-silica stimulated macrophages

The incidence of disease relating to nanoparticle exposure has been rising rapidly in recent years, for which there is no effective treatment. Macrophage is suggested to play a crucial role in the development of pulmonary disease. To investigate the changes in macrophage after being stimulated by nanometer silica dust and to explore potential biomarkers and signaling pathways, the gene chip GSE13005 was downloaded from Gene Expression Omnibus database, which contained 21 samples: 3 samples per group and 7 groups in total. Macrophages in the control group were cultured in serum-free medium, while the experimental groups were treated with nanometer silica dust in different sizes and concentrations, respectively. To identify the differentially expressed genes and explore their potential functions, we adopted the gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis and also constructed protein-protein interaction network. As a result, 1972 differentially expressed genes were identified from 22,690 microarray data in the gene chip, 1069 genes were upregulated and 903 genes were downregulated. Results of the gene ontology analysis indicated that the differentially expressed genes were widely distributed in intracellular and extracellular regions, regulating macrophage apoptosis, inflammatory response, and cell differentiation. The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that the majority of differentially expressed genes were enriched in cytokine-cytokine receptor interaction, cancer or phagosome transcriptional misregulation. The top 10 hub genes, S100a9, Nos3, Psmd14, Psmd4, Lck, Atp6v1h, Jun, Foxh1, Pex14, and Fadd were identified from protein-protein interaction network. In addition, Nos3, Psmd14, Atp6v1h, and Jun were clustered into module M2 (r_c = 0.74, p < 0.01), which mainly regulates cell carcinogenesis and antivirus process. In conclusion, differentially expressed genes screened from this study may provide new insights into the exploration of mechanisms, biomarkers, and therapeutic targets for diseases relating to nanoparticle exposure.

Lung cancer in patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease of unknown etiology. With a gradually increasing worldwide prevalence and a mortality rate exceeding that of many cancers, IPF diagnosis and management are critically important and require a comprehensive multidisciplinary approach. This approach also involves assessment of comorbid conditions, such as lung cancer, that exerts a dramatic impact on disease survival. Emerging evidence suggests that progressive lung scarring in the context of IPF represents a risk factor for lung carcinogenesis. Both disease entities present with major similarities in terms of pathogenetic pathways, as well as potential causative factors, such as smoking and viral infections. Besides disease pathogenesis, anti-cancer agents, including nintedanib, have been successfully applied in the treatment of patients with IPF while an oncologic approach with a cocktail of several pleiotropic anti-fibrotic agents is currently in the therapeutic pipeline of IPF. Nevertheless, epidemiologic association between IPF and lung cancer does not prove causality. Currently there is significant lack of knowledge supporting a direct association between lung fibrosis and cancer reflecting to disappointing therapeutic algorithms. An optimal therapeutic strategy for patients with both IPF and lung cancer represents an amenable need. This review article synthesizes the current state of knowledge regarding pathogenetic commonalities between IPF and lung cancer and focuses on clinical and therapeutic data that involve both disease entities.

Extracellular matrix remodeling in idiopathic pulmonary fibrosis. It is the 'bed' that counts and not 'the sleepers'

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease characterized by irreversible fibrosis. Current disease pathogenesis assumes an aberrant wound healing process in response to repetitive injurious stimuli leading to apoptosis of epithelial cells, activation of fibroblasts and accumulation of extracellular matrix (ECM). Particularly, lung ECM is a highly dynamic structure that lies at the core of several physiological and developmental pathways. The scope of this review article is to summarize current knowledge on the role of ECM in the pathogenesis of IPF, unravel novel mechanistic data and identify future more effective therapeutic targets. Areas covered: The exact mechanisms through which lung microenvironment activates fibroblasts and inflammatory cells, regulates profibrotic signaling cascades through growth factors, integrins and degradation enzymes ultimately leading to excessive matrix deposition are discussed. Furthermore, the potential therapeutic usefulness of specific inhibitors of matrix deposition or activators of matrix degradation pathways are also presented. Expert commentary: With a gradually increasing worldwide incidence IPF still present a major challenge in clinical research due to its unknown etiopathogenesis and current ineffective treatment approaches. Today, there is an amenable need for more effective therapeutic targets and ECM components may represent one.