Heat shock protein 70 protects against bleomycin-induced pulmonary fibrosis in mice

Geranylgeranylacetone, an inducer of heat shock protein 70, attenuates pulmonary fibrosis via inhibiting NF-κB/NOX4/ROS signalling pathway in vitro and in vivo

Idiopathic pulmonary fibrosis (IPF) is a devastating and progressive pulmonary disease which is characterized by epithelial cell damage and extracellular collagen deposition. To date, the therapeutic options for IPF are still very limited, so the relevant mechanisms need to be explored. Heat shock protein 70 (HSP70), which has protective versus antitumor effects on cells under stress, is a member of the heat shock protein family. In the current study, qRT-PCR, western blotting, immunofluorescence staining, and migration assays were used to explore the Epithelial-mesenchymal transition (EMT) process in BEAS-2B cells. Moreover, the role of GGA in the process of pulmonary fibrosis was detected by HE, Masson staining, pulmonary function test and immunohistochemistry in C57BL/6 mice. Our results indicated that GGA, as an inducer of HSP70, enhanced the transformation of BEAS-2B cells from epithelial to mesenchymal cells through the NF-κB/NOX4/ROS (reactive oxygen species) signalling pathway and could significantly reduce apoptosis of BEAS-2B cells induced by TGF-β1(Transforming growth factor β1) in vitro. In vivo studies demonstrated that HSP70-inducing drugs, such as GGA, attenuated pulmonary fibrosis progression induced by bleomycin (BLM). Collectively, these results suggested that overexpression of HSP70 attenuated pulmonary fibrosis induced by BLM in C57BL/6 mice and EMT process induced by TGF-β1 through NF-κB/NOX4/ROS pathway in vitro. Thus, HSP70 might be a potential therapeutic strategy for human lung fibrosis.

GGA (geranylgeranylacetone) ameliorates bleomycin-induced lung inflammation and pulmonary fibrosis by inhibiting apoptosis and oxidative stress

BACKGROUND

Fibrosis is a response to ongoing cellular injury, disruption, and tissue remodeling, the pathogenesis of which is unknown, and is characterized by extracellular matrix deposition. The antifibrotic effect of Geranylgeranylacetone (GGA), as an inducer of Heat shock protein 70 (HSP70), in liver, kidney and pulmonary fibrosis has been supported by multiple preclinical evidence. However, despite advances in our understanding, the precise roles of HSP70 in fibrosis require further investigation. The purpose of this study was to investigate whether GGA could participate in the progression of pulmonary fibrosis in mice through apoptosis, oxidative stress and inflammation.

METHODS AND RESULTS

B-cell lymphoma-2(Bcl-2) and Bcl2-Associated X (Bax) are two proteins related to apoptosis. Anti-apoptotic factor Bcl-2 and pro-apoptotic factor Bax are often involved in the apoptotic process in the form of dimer. Immunofluorescence and Western blot results showed that bleomycin (BLM) and transforming growth factor-β (TGF-β) inhibited Bcl-2 expression and promoted Bax expression in vitro and in vivo, respectively. In contrast, GGA treatment reverses this change. Reactive oxygen species (ROS), Malondialdehyde (MDA) and superoxide dismutase (SOD) are markers of oxidative stress, which often reflect oxidative injury of cells. The detection of ROS, MDA and SOD expression showed that TGF-β and BLM treatment could significantly promote oxidative stress, while GGA treatment could alleviate oxidative stress damage. In addition, BLM significantly elevated Tumor necrosis factor-α(TNF-α), Interleukin1β (IL-1β) and Interleukin 6 (IL-6), while scutellarin reversed the above alterations except for that of GGA.

RESULTS

Taken together, GGA suppressed apoptotic, oxidative stress and inflammation in BLM-induced pulmonary fibrosis.

Alvespimycin Exhibits Potential Anti-TGF-β Signaling in the Setting of a Proteasome Activator in Rats with Bleomycin-Induced Pulmonary Fibrosis: A Promising Novel Approach

Idiopathic pulmonary fibrosis (IPF) is an irreversible and life-threatening lung disease of unknown etiology presenting only a few treatment options. TGF-β signaling orchestrates a cascade of events driving pulmonary fibrosis (PF). Notably, recent research has affirmed the augmentation of TGF-β receptor (TβR) signaling via HSP90 activation. HSP90, a molecular chaperone, adeptly stabilizes and folds TβRs, thus intricately regulating TGF-β1 signaling. Our investigation illuminated the impact of alvespimycin, an HSP90 inhibitor, on TGF-β-mediated transcriptional responses by inducing destabilization of TβRs. This outcome stems from the explicit interaction of TβR subtypes I and II with HSP90, where they are clients of this cellular chaperone. It is worth noting that regulation of proteasome-dependent degradation of TβRs is a critical standpoint in the termination of TGF-β signal transduction. Oleuropein, the principal bioactive compound found in Olea europaea, is acknowledged for its role as a proteasome activator. In this study, our aim was to explore the efficacy of a combined therapy involving oleuropein and alvespimycin for the treatment of PF. We employed a PF rat model that was induced by intratracheal bleomycin infusion. The application of this dual therapy yielded a noteworthy impediment to the undesired activation of TGF-β/mothers against decapentaplegic homologs 2 and 3 (SMAD2/3) signaling. Consequently, this novel combination showcased improvements in both lung tissue structure and function while also effectively restraining key fibrosis markers such as PDGF-BB, TIMP-1, ACTA2, col1a1, and hydroxyproline. On a mechanistic level, our findings unveiled that the antifibrotic impact of this combination therapy likely stemmed from the enhanced degradation of both TβRI and TβRII. In conclusion, the utilization of proteasomal activators in conjunction with HSP90 inhibitors ushers in a promising frontier for the management of PF.

Inflammation in Pulmonary Hypertension and Edema Induced by Hypobaric Hypoxia Exposure

Exposure to high altitudes generates a decrease in the partial pressure of oxygen, triggering a hypobaric hypoxic condition. This condition produces pathophysiologic alterations in an organism. In the lung, one of the principal responses to hypoxia is the development of hypoxic pulmonary vasoconstriction (HPV), which improves gas exchange. However, when HPV is exacerbated, it induces high-altitude pulmonary hypertension (HAPH). Another important illness in hypobaric hypoxia is high-altitude pulmonary edema (HAPE), which occurs under acute exposure. Several studies have shown that inflammatory processes are activated in high-altitude illnesses, highlighting the importance of the crosstalk between hypoxia and inflammation. The aim of this review is to determine the inflammatory pathways involved in hypobaric hypoxia, to investigate the key role of inflammation in lung pathologies, such as HAPH and HAPE, and to summarize different anti-inflammatory treatment approaches for these high-altitude illnesses. In conclusion, both HAPE and HAPH show an increase in inflammatory cell infiltration (macrophages and neutrophils), cytokine levels (IL-6, TNF-α and IL-1β), chemokine levels (MCP-1), and cell adhesion molecule levels (ICAM-1 and VCAM-1), and anti-inflammatory treatments (decreasing all inflammatory components mentioned above) seem to be promising mitigation strategies for treating lung pathologies associated with high-altitude exposure.

Nintedanib induces gene expression changes in the lung of induced-rheumatoid arthritis–associated interstitial lung disease mice

Nintedanib is a multi-tyrosine kinase inhibitor widely used to treat progressive fibrosing interstitial lung diseases because it slows the reduction in forced vital capacity. However, the prognosis for patients treated with nintedanib remains poor. To improve nintedanib treatment, we examined the effects of nintedanib on gene expression in the lungs of induced-rheumatoid arthritis–associated interstitial lung disease model mice, which develop rheumatoid arthritis and subsequent pulmonary fibrosis. Using next-generation sequencing, we identified 27 upregulated and 130 downregulated genes in the lungs of these mice after treatment with nintedanib. The differentially expressed genes included mucin 5B and heat shock protein 70 family genes, which are related to interstitial lung diseases, as well as genes associated with extracellular components, particularly the myocardial architecture, suggesting unanticipated effects of nintedanib. Of the genes upregulated in the nintedanib-treated lung, expression of regulatory factor X2, which is suspected to be involved in cilia movement, and bone morphogenetic protein receptor type 2, which is involved in the pathology of pulmonary hypertension, was detected by immunohistochemistry and RNA in situ hybridization in peripheral airway epithelium and alveolar cells. Thus, the present findings indicate a set of genes whose expression alteration potentially underlies the effects of nintedanib on pulmonary fibrosis. It is expected that these findings will contribute to the development of improved nintedanib strategies for the treatment of progressive fibrosing interstitial lung diseases.

Heat shock proteins in pulmonary fibrosis: pawns of cell homeostasis

Idiopathic lung fibrosis (IPF) is a fatal disease that primarily affects the elderly. Up to date, the specific pathophysiology of IPF remains unknown. However, it is theorized to be caused by chronic repetitive injuries to the alveolar epithelium, eventually exhausting the stem cell capacity and activating pathological pathways. Heat shock proteins (HSPs), a category of stress response proteins, are also suggested to contribute to IPF pathophysiology. Furthermore, HSPs are key components in the regulation of cell homeostasis and act as chaperones for a multitude of new proteins. This review thoroughly evaluates the roles that specific HSPs, HSP90, HSP70, and HSP47, have in the fibrotic process. A close look into the roles of these HSPs in IPF pathophysiology will give valuable insight into the future of IPF treatment and prevention.

Possible Applications of Hyperbaric Oxygen Therapy-Narrative Review

Hyperbaric oxygen therapy is a method supporting the treatment of many diseases. Oxygen therapy treatments are conducted in hyperbaric chambers, in which patients breathe pure, 100% oxygen with higher than atmospheric pressure. This allows to increase the amount of oxygen supplied to all cells of the body many times over. The treatment with hyperbaric oxygen therapy enables the patient to recover faster and be fully active, and also reduces the costs of standard treatment.

The aim of the study was to summarize the possible applications of hyperbaric oxygen therapy. The available literature in the PUBMED database was reviewed in September 2022 with the use of the phrases ‘hyperbaric oxygen therapy’, ‘therapeutic applications’. The indications for therapy in a hyperbaric chamber are all kinds of diseases, both acute and chronic. The method supports the nourishment and regeneration of cells and tissues of the organism, and also slows down the aging process. However, due to the possible side effects of such therapy, patients should be qualified for its use after a careful analysis of their clinical condition and coexisting diseases. To sum up: hyperbaric oxygen therapy is most often used in the treatment of skin diseases and injuries, burns, and peripheral vascular diseases.

FK506-Binding Protein 13 Expression Is Upregulated in Interstitial Lung Disease and Correlated with Clinical Severity. A Potentially Protective Role

Pulmonary fibrosis is a progressive lung disease characterized by myofibroblast accumulation and excessive extracellular matrix deposition. We sought to investigate the role of FKBP13 (13-kD FK506-binding protein), an endoplasmic reticulum-resident molecular chaperone, in various forms of pulmonary fibrosis. We first characterized the gene and protein expression of FKBP13 in lung biopsy specimens from 24 patients with idiopathic pulmonary fibrosis and 17 control subjects. FKBP13 expression was found to be elevated in the fibrotic regions of idiopathic pulmonary fibrosis lung tissues and correlated with declining forced vital capacity and dyspnea severity. FKBP13 expression was also increased in lung biopsy specimens of patients with hypersensitivity pneumonitis, rheumatoid arthritis, and sarcoidosis-associated interstitial lung disease. We next evaluated the role of this protein using FKBP13^-/- mice in a bleomycin model of pulmonary fibrosis. Animals were assessed for lung function and histopathology at different stages of lung injury including the inflammatory (Day 7), fibrotic (Day 21), and resolution (Day 50) phases. FKBP13^-/- mice showed increased infiltration of inflammatory cells and cytokines at Day 7, increased lung elastance and fibrosis at Day 21, and impaired resolution of fibrosis at Day 50. These changes were associated with an increased number of cells that stained positive for TUNEL and cleaved caspase 3 in the FKBP13^-/- lungs, indicating a heightened cellular sensitivity to bleomycin. Our findings suggest that FKBP13 is a potential biomarker for severity of interstitial lung diseases and that it has a biologically relevant role in protecting mice against bleomycin-induced injury, inflammation, and fibrosis.

MYH9 Inhibition Suppresses TGF-β1-Stimulated Lung Fibroblast-to-Myofibroblast Differentiation

Previous cDNA microarray results showed that MYH9 gene expression levels are increased in TGF-β1-stimulated lung fibroblast. Recently, our proteomic results revealed that the expression levels of MYH9 protein are notably upregulated in lung tissues of bleomycin-treated rats. However, whether MYH9 plays a critical role in the differentiation of fibroblast remains unclear. Herein, we demonstrated that TGF-β1 increased MYH9 expression, and siRNA-mediated knockdown of MYH9 and pharmacological inhibition of MYH9 ATPase activity remarkably repressed TGF-β1-induced lung fibroblast-to-myofibroblast differentiation. TGF-β1-stimulated MYH9 induction might be via ALK5/Smad2/3 pathway but not through noncanonical pathways, including p38 mitogen-activated kinase, and Akt pathways in lung fibroblasts. Our results showed that MYH9 inhibition suppressed TGF-β1-induced lung fibroblast-to-myofibroblast differentiation, which provides valuable information for illuminating the pathological mechanisms of lung fibroblast differentiation, and gives clues for finding new potential target for pulmonary fibrosis treatment.

The Role of Heat Shock Protein 70 kDa in Asthma

Asthma is a complex chronic disorder of the airways, affecting immune and structural cells and inducing both protein and tissue remodeling. Heat shock proteins 70 kDa (HSP70s) are highly conserved members of the stress-induced family, possessing precisely described chaperone activity. There is growing evidence of a tight relationship between inflammatory diseases of different origins and the elevation of local HSP70 expression and secretion. Although extracellular HSP70 does not serve as a common marker of asthma, elevated HSP70 levels have been detected in the peripheral blood serum and sputum of patients with asthma, as well as in the bronchoalveolar lavage fluid of mice with induced allergic airway inflammation. Possessing diverse immunomodulating properties, extracellular HSP70 can manifest different activities in airway inflammatory processes and asthma, acting either as a pro-inflammatory trigger, or an anti-inflammatory agent. This review will discuss the effects and possible mechanisms concerning HSP70 implication in airway inflammation regulation in asthma. We examine ATPase and chaperone activities of HSP70 as potential modulators of immune responses in asthma. Given the crucial role of a chronic inflammatory response in asthma, understanding the effects of HSP70 on immune and structural cells may reveal new perspectives for the therapeutic control of inflammation.

The role of heat shock proteins in the regulation of fibrotic diseases

Heat shock proteins (HSPs) are key players to restore cell homeostasis and act as chaperones by assisting the folding and assembly of newly synthesized proteins and preventing protein aggregation. Recently, evidence has been accumulating that HSPs have been proven to have other functions except for the classical molecular chaperoning in that they play an important role in a wider range of fibrotic diseases via modulating cytokine induction and inflammation response, including lung fibrosis, liver fibrosis, and idiopathic pulmonary fibrosis. The recruitment of inflammatory cells, a large number of secretion of pro-fibrotic cytokines such as transforming growth factor-β1 (TGF-β1) and increased apoptosis, oxidative stress, and proteasomal system degradation are all events occurring during fibrogenesis, which might be associated with HSPs. However, their role on fibrotic process is not yet fully understood. In this review, we discuss new discoveries regarding the involvement of HSPs in the regulation of organ and tissue fibrosis, and note recent findings suggesting that HSPs may be a promising therapeutic target for improving the current frustrating outcome of fibrotic disorders.

Damage-Associated Molecular Patterns and Their Signaling Pathways in Primary Blast Lung Injury: New Research Progress and Future Directions

Primary blast lung injury (PBLI) is a common cause of casualties in wars, terrorist attacks, and explosions. It can exist in the absence of any other outward signs of trauma, and further develop into acute lung injury (ALI) or a more severe acute respiratory distress syndrome (ARDS). The pathogenesis of PBLI at the cellular and molecular level has not been clear. Damage-associated molecular pattern (DAMP) is a general term for endogenous danger signals released by the body after injury, including intracellular protein molecules (HMGB1, histones, s100s, heat shock proteins, eCIRP, etc.), secretory protein factors (IL-1β, IL-6, IL-10, TNF-α, VEGF, complements, etc.), purines and pyrimidines and their derived degradation products (nucleic acids, ATP, ADP, UDPG, uric acid, etc.), and extracellular matrix components (hyaluronic acid, fibronectin, heparin sulfate, biglycan, etc.). DAMPs can be detected by multiple receptors including pattern recognition receptors (PRRs). The study of DAMPs and their related signaling pathways, such as the mtDNA-triggered cGAS-YAP pathway, contributes to revealing the molecular mechanism of PBLI, and provides new therapeutic targets for controlling inflammatory diseases and alleviating their symptoms. In this review, we focus on the recent progress of research on DAMPs and their signaling pathways, as well as the potential therapeutic targets and future research directions in PBLI.

The ageing lung under stress

Healthy ageing of the lung involves structural changes but also numerous cell-intrinsic and cell-extrinsic alterations. Among them are the age-related decline in central cellular quality control mechanisms such as redox and protein homeostasis. In this review, we would like to provide a conceptual framework of how impaired stress responses in the ageing lung, as exemplified by dysfunctional redox and protein homeostasis, may contribute to onset and progression of COPD and idiopathic pulmonary fibrosis (IPF). We propose that age-related imbalanced redox and protein homeostasis acts, amongst others (e.g.cellular senescence), as a “first hit” that challenges the adaptive stress-response pathways of the cell, increases the level of oxidative stress and renders the lung susceptible to subsequent injury and disease. In both COPD and IPF, additional environmental insults such as smoking, air pollution and/or infections then serve as “second hits” which contribute to persistently elevated oxidative stress that overwhelms the already weakened adaptive defence and repair pathways in the elderly towards non-adaptive, irremediable stress thereby promoting development and progression of respiratory diseases. COPD and IPF are thus distinct horns of the same devil, “lung ageing”.

Biomarkers and their potential functions in idiopathic pulmonary fibrosis

Introduction: Idiopathic pulmonary fibrosis (IPF) is a chronic, devastating, and progressive lung disease that is characterized by fibrosis and respiratory failure. IPF holds high morbidity and poor prognosis and still faces considerable problems of reliable diagnosis and valid prognosis. A growing body of literature have reported changes in the level of various biomarkers in IPF patients, which means that they are expected to become a new tool for the clinical practice of IPF.Areas covered: We reviewed the recent literature about biomarkers and focus on the role they play in IPF. We systematically searched Medline/PubMed through February 2020. Many works of literature have shown that a variety of biomolecules and genomics played multiple roles in the diagnosis or differential diagnosis, prognosis, and indication of acute deterioration of IPF and so on.Expert opinion: Significant advances have been made in the role of biomarkers for IPF these years; however, current data indicate that a single biomarker is unlikely to have a transformative effect on clinical practice; therefore, the combined effect of various biomarkers can be considered to improve the accuracy of diagnosis and prognosis. Further research of biomarkers may provide new insights for the diagnosis, prognosis, and even therapy of IPF.

HSP70 induction by bleomycin metal core analogs

Induction of heat shock protein 70 (HSP70) is known to be effective against various diseases. We are interested in HSP70 induction capability of an antitumor antibiotic bleomycin which produces oxidative stress by iron chelate formation and oxygen activation in a cell. The HSP70 induction activity of bleomycin and its six metal core analogs was examined, and a compound HPH-1Trt of 10 μM was found to induce this protein in a pheochromocytoma cell line and some T cell and monocytic cell lines. Its mechanism is increase of HSP70 mRNA, but higher concentration of this compound showed toxicity. Two new derivatives were then synthesized, and one of them named DHPH-1Trt was shown to have less toxicity and higher HSP70 induction activity. This study would lead to a clue for new HSP70 inducer clinically used in near future.

Intracellular Heat Shock Protein 70 Deficiency in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) pathogenesis has been postulated to involve a variety of mechanisms associated with the aging process, including loss of protein homeostasis (proteostasis). Heat shock proteins are cellular chaperones that serve a number of vital maintenance and repair functions, including the regulation of proteostasis. Previously published data have implicated heat shock protein 70 (Hsp70) in the development of pulmonary fibrosis in animal models. We sought to identify alterations in Hsp70 expression in IPF lung. Hsp70 mRNA and protein were decreased in primary fibroblasts cultured from IPF versus normal donor lung tissue. In addition to cultured fibroblasts, Hsp70 expression was decreased in intact IPF lung, a stressed environment in which upregulation of protective heat shock proteins would be anticipated. In support of a mechanistic association between decreased Hsp70 and fibrosis, cultured primary lung fibroblasts deficient in Hsp70 secreted increased extracellular matrix proteins. Treatment of primary normal human lung fibroblasts in vitro with either of the profibrotic molecules IGFBP5 (insulin-like growth factor-binding protein 5) or transforming growth factor-β1 downregulated Hsp70, suggesting Hsp70 is a downstream target in the fibrotic cascade. Hsp70-knockout mice subjected to an inhalational bleomycin model of pulmonary fibrosis demonstrated accelerated fibrosis versus wild-type control animals. We therefore conclude that reduced Hsp70 protein contributes to fibrosis and that interventions aimed at restoring normal expression of Hsp70 represent a novel therapeutic strategy for pulmonary fibrosis.

Chronic corticosterone exposure induces liver inflammation and fibrosis in association with m6A-linked post-transcriptional suppression of heat shock proteins in chicken

Our previous study had shown that chronic corticosterone (CORT) exposure causes excessive fat deposition in chicken liver, yet it remains unknown whether it is associated with inflammation and fibrosis. In general, heat shock proteins (HSPs) are activated in response to acute stress to play a cytoprotective role, and this activation is associated with m6A-mediated post-transcriptional regulation. However, changes of HSPs and the m6A methylation on their mRNAs in response to chronic CORT treatment in chicken liver have not been reported. In this study, chronic CORT exposure induced inflammation and fibrosis in chicken liver, associated with significantly modulated expression of HSPs that was significantly upregulated at mRNA level yet downregulated at protein level. Concurrently, m6A methyltransferases METTL3 content was upregulated together with the level of m6A methylation on HSPs transcripts. The m6A-seq analysis revealed 2-6 significantly (P < 0.05) hypermethylated m6A peaks in the mRNA of 4 different species of HSPs in CORT-treated chicken liver. HSP90B1 transcript had 6 differentially methylated m6A peaks among which peaks on exon 16 and exon 17 showed 3.14- and 4.72-fold of increase, respectively. Mutation of the 8 predicted m6A sites on exon 16 and exon 17 resulted in a significant (P < 0.05) increase in eGFP-fused content of HSP90B1 exon 16 and exon 17 fragment in 293 T cells, indicating a possible role of m6A in post-transcriptional regulation of HSPs. In conclusion, chronic CORT exposure induces inflammation and fibrosis in chicken liver along with an increase in the levels and m6A methylation of several HSPs mRNAs; HSPs levels were however reduced under the indicated conditions. Results presented suggest that the reduction in HSPs levels may be associated with m6A methylation in CORT-exposed chickens.

When Wounds Are Good for You: The Regenerative Capacity of Fractional Resurfacing and Potential Utility in Chronic Wound Prevention

Significance: Fractional resurfacing involves producing arrays of microinjuries on the skin, by thermal or mechanical means, to trigger tissue regeneration. Originally developed for cosmetic enhancement, fractional resurfacing induces a broad array of improvements in the structural and functional qualities of the treated skin and is especially effective at returning defective skin to a more normal state. In addition to fascinating questions about the nature of this remarkable regenerative capacity, there may be potential utility in ulcer prevention by halting or even reversing the progressive decline in overall skin quality that usually precedes chronic wound development. Recent Advances: Photoaging and scarring are the two skin defects most commonly treated by fractional resurfacing, and the treatment produces profound and long-lasting improvements in skin quality, both clinically and at the cellular/histologic level. Chronic wounds usually occur in skin that is compromised by various pathologic factors, and many of the defects found in this ulcer-prone skin are similar to those that have seen improvements after fractional resurfacing. Critical Issues: The mechanisms responsible for the regenerative capacity of fractional resurfacing are mostly unknown, as is how ulcer-prone skin, which is usually afflicted by stressors external to the skin tissue itself, would respond to fractional resurfacing. Future Directions: Better understanding of the cellular and molecular mechanisms underlying the unique healing response to fractional resurfacing could reveal fundamental information about adult tissue regeneration, lead to improvements in current applications, as well as new therapies in other pathologic conditions.

Idebenone has preventative and therapeutic effects on pulmonary fibrosis via preferential suppression of fibroblast activity

Alveolar epithelial injury induced by reactive oxygen species (ROS) and abnormal collagen production by activated fibroblasts (myofibroblasts) is involved in the onset and exacerbation of idiopathic pulmonary fibrosis (IPF). Compared with alveolar epithelial cells, lung fibroblasts, especially myofibroblasts, exhibit an apoptosis-resistance phenotype (apoptosis paradox) that appears to be involved in IPF pathogenesis. Thus, we screened for chemicals eliciting preferential cytotoxicity of LL29 cells (lung fibroblasts from an IPF patient) compared with A549 cells (human lung alveolar epithelial cell line) from medicines already in clinical use. We identified idebenone, a synthetic analogue of coenzyme Q10 (CoQ₁₀, an antioxidant) that has been used clinically as a brain metabolic stimulant. Idebenone induced cell growth inhibition and cell death in LL29 cells at a lower concentration than in A549 cells, a feature that was not observed for other antioxidant molecules (such as CoQ₁₀) and two IPF drugs (pirfenidone and nintedanib). Administration of idebenone prevented bleomycin-induced pulmonary fibrosis and increased pulmonary ROS levels. Importantly, idebenone also improved pulmonary fibrosis and lung function when administered after the development of fibrosis, whereas administration of CoQ₁₀ similarly prevented bleomycin-induced pulmonary fibrosis, but had no effect after its development. Administration of idebenone, but not CoQ₁₀, suppressed bleomycin-induced increases in lung myofibroblasts. In vitro, treatment of LL29 cells with idebenone, but not CoQ₁₀, suppressed TGF-β–induced collagen production. These results suggest that in addition to antioxidant activity, idebenone exerts inhibitory activity on the function of lung fibroblasts, with the former activity being preventative and the latter therapeutic for bleomycin-induced fibrosis. Thus, we propose that idebenone may be more therapeutically beneficial for IPF patients than current treatments.

The Cytotoxic Effects of Geranylgeranylacetone Are Attenuated in the High-Glucose Condition

Geranylgeranylacetone (GGA) has been used as an antiulcer drug and also is known as inducer of heat shock protein 70 that has cytoprotective effects especially in hyperglycemic condition. In contrast, cytotoxicity of GGA has also been reported. Some studies have reported that GGA suppresses cell growth and induces apoptosis in cell models of human leukemia, ovarian carcinoma, and colon cancer in vitro. Therefore, the aim of this study was to determine whether GGA can have a cytotoxic effect on a human cervical cancer cell line (HeLa), human colorectal adenocarcinoma cells (Caco-2), and human embryonic kidney cells 293 (HEK) in normal-glucose and high-glucose environments (NG and HG, respectively). The results showed that 100 μM GGA inhibited proliferation of HeLa cells only in NG environment despite inhibiting proliferation of Caco-2 and HEK cells regardless of glucose concentration. Cell viability assay revealed that GGA decreased viability of HeLa, Caco-2, and HEK cells only in NG environment. Flow cytometric analyses revealed that the type of cell death was a combination of necrosis and apoptosis. Our study revealed that difference in cytotoxicity of GGA is influenced by glucose condition. The cytotoxic effects of GGA are attenuated in the HG condition. Since both cytotoxic and cytoprotective effects are reported about GGA, further research is needed about the mechanism of the cytotoxic effects.

Heat shock protein 70 is a positive regulator of airway inflammation and goblet cell hyperplasia in a mouse model of allergic airway inflammation

Heat shock proteins (Hsps) are highly conserved molecular chaperones that are ubiquitously expressed in all species to aid the solubilization of misfolded proteins, protein degradation, and transport. Elevated levels of Hsp70 have been found in the sputum, serum, and bronchoalveolar lavage (BAL) fluid of asthma patients and are known to correlate with disease severity. However, the function of Hsp70 in allergic airway inflammation has remained largely unknown. This study aimed to determine the role of Hsp70 in airway inflammation and remodeling using a mouse model of allergic airway inflammation. WT and Hsp70 double-knockout (Hsp70.1/.3^-/-) mice were sensitized and challenged intratracheally with Schistosoma mansoni soluble egg antigens (SEAs) to induce robust Th2 responses and airway inflammation in the lungs. The lack of Hsp70 resulted in a significant reduction in airway inflammation, goblet cell hyperplasia, and Th2 cytokine production, including IL-4, IL-5, and IL-13. An analysis of the BAL fluid suggested that Hsp70 is critically required for eosinophilic infiltration, collagen accumulation, and Th2 cytokine production in allergic airways. Furthermore, our bone marrow (BM) transfer studies show that SEA-induced airway inflammation, goblet cell hyperplasia, and Th2 cytokine production were attenuated in WT mice that were reconstituted with Hsp70-deficient BM, but these effects were not attenuated in Hsp70-deficient mice that were reconstituted with WT BM. Together, these studies identify a pathogenic role for Hsp70 in hematopoietic cells during allergic airway inflammation; this illustrates the potential utility of targeting Hsp70 to alleviate allergen-induced Th2 cytokines, goblet cell hyperplasia, and airway inflammation.

Triptolide inhibits migration and proliferation of fibroblasts from ileocolonic anastomosis of patients with Crohn's disease via regulating the miR‑16‑1/HSP70 pathway

Anastomotic fibrosis is highly likely to lead to reoperation in Crohn's disease (CD) patients. Triptolide (TPL) is considered to have anti-inflammatory and antifibrotic effects in a variety of autoimmune diseases, including CD. The present study aimed to investigate the effects of TPL on fibroblasts from strictured ileocolonic anastomosis of patients with CD and its underlying mechanism. Primary fibroblasts were obtained from strictured anastomosis tissue (SAT) samples and matched anastomosis-adjacent normal tissue (NT) samples which were collected from 10 CD patients who underwent reoperation because of anastomotic stricture. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to measure miR-16-1 and heat shock protein 70 (HSP70) levels. Western blotting was conducted to determine expression of HSP70, collagen I (Col-I), collagen III (Col-III) and α-smooth muscle actin (α-SMA) proteins. Agomir-16-1 and antagomir-16-1 were used to up and downregulate the expression of miR-16-1, respectively. Small interfering RNA (siRNA) was employed to inhibit the expression of HSP70. A wound healing assay was performed to measure the migration of fibroblasts. Cell proliferation was evaluated by MTT and 5-bromo-2-deoxyrudidine assays. Cell apoptosis was determined by caspase-3 activity and TUNEL assays. The results demonstrated that the levels of Col-I, Col-III and α-SMA were all significantly upregulated in SAT compared with NT. miR-16-1 levels in the SAT group were significantly compared with the NT group; conversely, the expression levels of HSP70 mRNA and protein in the SAT group were significantly lower compared with the NT group. Next, fibroblasts were treated with TPL to examine its effect on the miR-16-1/HSP70 pathway. The results demonstrated that the elevated expression of miR-16-1 in the SAT group was effectively inhibited by TPL treatment. Compared with the NT group, both the mRNA and protein levels of HSP70 were significantly downregulated in the SAT group cells, while TPL exhibited a strong promoting effect on HSP70 synthesis. Furthermore, upregulation of miR-16-1 reversed the effect of TPL on the miR-16-1/HSP70 pathway in fibroblasts from SAT. Overexpression of miR-16-1 significantly reversed the inhibitory effects of TPL treatment on migration, proliferation and extracellular matrix (ECM)-associated protein expression of fibroblasts from SAT. Finally, downregulation of miR-16-1 caused similar effects to the fibroblasts as the TPL treatment; however, the inhibitory effects on cell biological functions induced by antagomir-16-1 were all significantly reversed by HSP70 silencing. The present findings indicated that TPL may be a potential therapeutic option for postoperative anastomosis fibrosis of patients with CD. The miR-16-1/HSP70 pathway had a substantial role in the inhibitory effects of TPL on migration, proliferation and ECM synthesis rate of fibroblasts from strictured anastomosis tissues.

Transforming growth factor beta1 targets estrogen receptor signaling in bronchial epithelial cells

Background

Sex differences in idiopathic pulmonary fibrosis (IPF) suggest a protective role for estrogen (E2); however, mechanistic studies in animal models have produced mixed results. Reports using cell lines have investigated molecular interactions between transforming growth factor beta1 (TGF-β1) and estrogen receptor (ESR) pathways in breast, prostate, and skin cells, but no such interactions have been described in human lung cells. To address this gap in the literature, we investigated a role for E2 in modulating TGF-β1-induced signaling mechanisms and identified novel pathways impacted by estrogen in bronchial epithelial cells.

Methods

We investigated a role for E2 in modulating TGF-β1-induced epithelial to mesenchymal transition (EMT) in bronchial epithelial cells (BEAS-2Bs) and characterized the effect of TGF-β1 on ESR mRNA and protein expression in BEAS-2Bs. We also quantified mRNA expression of ESRs in lung tissue from individuals with IPF and identified potential downstream targets of E2 signaling in BEAS-2Bs using RNA-Seq and gene set enrichment analysis.

Results

E2 negligibly modulated TGF-β1-induced EMT; however, we report the novel observation that TGF-β1 repressed ESR expression, most notably estrogen receptor alpha (ESR1). Results of the RNA-Seq analysis showed that TGF-β1 and E2 inversely modulated the expression of several genes involved in processes such as extracellular matrix (ECM) turnover, airway smooth muscle cell contraction, and calcium flux regulation. We also report that E2 specifically modulated the expression of genes involved in chromatin remodeling pathways and that this regulation was absent in the presence of TGF-β1.

Conclusions

Collectively, these results suggest that E2 influences unexplored pathways that may be relevant to pulmonary disease and highlights potential roles for E2 in the lung that may contribute to sex-specific differences.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0861-5) contains supplementary material, which is available to authorized users.

Screening and Preliminary Verification of a Phage Display Single-Chain Antibody Library Against Coal Workers' Pneumoconiosis

OBJECTIVES

To construct a phage display human antibody library (PDHAL) against pneumoconiosis for the diagnosis and treatment of coal worker pneumoconiosis (CWP).

METHODS

The PDHAL was established via CWP blood and six positive antibodies were discovered. 867 coal workers (558 CWP and 309 without CWP) and 393 controls were recruited to validate the results.

RESULTS

A PDHAL against CWP was established, from which six strong positive clones were selected, sequenced and identified as VEGF, interleukin-18, HSP70, HER3, Gz-B and RF. Logistic regression analysis revealed that VEGF (OR (95% CI), 0.02 (0.01to 0.07), P < 0.05), RF-Ab (OR (95% CI): 0.46 (0.28 to 0.73), P < 0.05) and HSP70/HSP-70-Ab (OR (95% CI): 0.71 (0.53 to 0.95), P < 0.05) were protective factors for CWP after adjustment of confounding factors.

CONCLUSION

The serum VEGF, RF-Ab and HSP-70/HSP-70 antibodies were potential biomarkers for diagnosis and treatment of CWP.

Biomarkers in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, debilitating, fibrotic lung disease leading to respiratory failure and ultimately to death. Being the prototype of interstitial lung diseases, IPF is characterized by marked heterogeneity regarding its clinical course. Despite significant progress in the understanding of its pathogenesis, we still cannot reliably predict the course of the disease and the response to treatment of an individual patient. Non-invasive biomarkers, in particular serum biomarkers, for the (early) diagnosis, differential diagnosis, prognosis and prediction of therapeutic response are urgently needed. Numerous molecules involved in alveolar epithelial cell injury, fibroproliferation and matrix remodeling as well as immune regulation have been proposed as potential biomarkers. Furthermore, genetic variants of TOLLIP, MUC5B, and other genes are associated with a differential response to treatment and with the development and/or the prognosis of IPF. Additionally, the bacterial signature in IPF lungs, as shown from microbiome analyses, as well as mitochondrial DNA seem to have promising roles as biomarkers. Moreover, combination of multiple biomarkers may identify comprehensive biomarker signatures in IPF patients. However, there is still a long way until these potential biomarkers complete or substitute for the clinical and functional parameters currently available for IPF.

Postmarketing surveillance study of erlotinib plus gemcitabine for pancreatic cancer in Japan: POLARIS final analysis

Objective

Erlotinib plus gemcitabine is approved in Japan for the treatment of metastatic pancreatic cancer. The POLARIS surveillance study investigated safety (focusing on interstitial lung disease [ILD]) and efficacy of erlotinib plus gemcitabine in Japanese pancreatic cancer patients.

Methods

Patients receiving erlotinib plus gemcitabine for pancreatic cancer in Japan between July 2011 and August 2012 were enrolled. ILD-like events were independently confirmed by a review committee. Overall survival (OS) and progression-free survival (PFS) were assessed, and risk factors for ILD occurrence were analyzed by multivariate Cox regression analysis.

Results

Safety data were available for 843 patients and efficacy data for 841. Adverse drug reactions were reported in 83.5% of patients, no new safety signals were identified. ILD events were confirmed by the review committee in 52 patients (6.2%), with two fatal cases (0.2%). Median time from initial erlotinib treatment to ILD events was 70.5 days. Of the 52 patients with ILD events, 86.5% improved or fully recovered from ILD (median time 24 days). Multivariate analysis identified previous or concurrent lung disease (hazard ratio [HR], 2.2; 95% confidence interval [CI], 1.0-4.5; P = 0.0365) and ≥3 organs with metastases (HR, 4.2; 95% CI, 2.2-8.2; P < 0.0001) as potential ILD risk factors. Accumulated OS rate at 28 weeks was 68.2%, and median PFS was 92 days (95% CI, 86-101).

Conclusions

Erlotinib plus gemcitabine has an acceptable safety and efficacy profile in pancreatic cancer; however, patients should be assessed for previous/concurrent lung disease and metastatic burden, before and during treatment.

Geranylgeranylacetone Ameliorates Intestinal Radiation Toxicity by Preventing Endothelial Cell Dysfunction

Radiation-induced intestinal toxicity is common among cancer patients after radiotherapy. Endothelial cell dysfunction is believed to be a critical contributor to radiation tissue injury in the intestine. Geranylgeranylacetone (GGA) has been used to treat peptic ulcers and gastritis. However, the protective capacity of GGA against radiation-induced intestinal injury has not been addressed. Therefore, we investigated whether GGA affects intestinal damage in mice and vascular endothelial cell damage in vitro. GGA treatment significantly ameliorated intestinal injury, as evident by intestinal crypt survival, villi length and the subsequently prolonged survival time of irradiated mice. In addition, intestinal microvessels were also significantly preserved in GGA-treated mice. To clarify the effect of GGA on endothelial cell survival, we examined endothelial function by evaluating cell proliferation, tube formation, wound healing, invasion and migration in the presence or absence of GGA after irradiation. Our findings showed that GGA plays a role in maintaining vascular cell function; however, it does not protect against radiation-induced vascular cell death. GGA promoted endothelial function during radiation injury by preventing the loss of VEGF/VEGFR1/eNOS signaling and by down-regulating TNFα expression in endothelial cells. This finding indicates the potential impact of GGA as a therapeutic agent in mitigating radiation-induced intestinal damage.

Protective and therapeutic effect of felodipine against bleomycin-induced pulmonary fibrosis in mice

Idiopathic pulmonary fibrosis (IPF) involves alveolar epithelial injury and abnormal collagen production caused by activated fibroblasts; transforming growth factor (TGF)-β1 is implicated in this activation. In this study, we screened for chemicals capable of inhibiting TGF-β1-induced collagen production in cultured fibroblasts from medicines already in clinical use. We selected felodipine based on its extent of collagen production inhibition, clinical safety profile, and other pharmacological activity. Felodipine is a dihydropyridine Ca²⁺ channel blocker that has been used clinically to treat patients with high blood pressure. Felodipine suppressed collagen production within LL29 cells in the presence of TGF-β1, but not in its absence. Intratracheal administration of felodipine prevented bleomycin-induced pulmonary fibrosis, alteration of lung mechanics and respiratory dysfunction. Felodipine also improved pulmonary fibrosis, as well as lung and respiratory function when administered after fibrosis development. Furthermore, administration of felodipine suppressed a bleomycin-induced increase in activated fibroblasts in the lung. We also found other dihydropyridine Ca²⁺ channel blockers (nifedipine and benidipine) inhibited collagen production in vitro and partially prevented bleomycin-induced pulmonary fibrosis, alteration of lung mechanics and respiratory dysfunction in vivo. We propose that these Ca²⁺ channel blockers may be therapeutically beneficial for IPF patients.

"Heat shock protein 70 in pancreatic diseases: Friend or foe"

The heat shock response in pancreatitis that is activated via HSP70 protects acinar cells through multiple simultaneous mechanisms. It inhibits trypsinogen activation and modulates NF-κB signaling to limit acinar cell injury. On the other hand, HSP70 is overexpressed in pancreatic cancer and is hijacked by the cellular machinery to inhibit apoptosis. Inhibition of HSP70 in pancreatic cancer by a novel compound, Minnelide, has shown considerable clinical promise.

Treatment with Geranylgeranylacetone Induces Heat Shock Protein 70 and Attenuates Neonatal Hyperoxic Lung Injury in a Model of Bronchopulmonary Dysplasia

Purpose

Bronchopulmonary dysplasia (BPD) is a respiratory complication characterized by abnormal alveolar development in premature infants. Geranylgeranylacetone (GGA) can induce heat shock protein (HSP) 70, which has cytoprotective effects against various stressors. Here, we investigated whether GGA protected neonatal lungs from hyperoxic stress in a murine BPD model, and measured the serum HSP70 levels in preterm humans treated with oxygen.

Methods

Newborn mice were exposed to >90% oxygen and administered GGA or vehicle alone orally on days 1, 2, and 3 of life. At 2 days of age, HSP70 expression in the lung was determined by western blotting. At 8 days of age, the lungs were processed for histological analysis. Radial alveolar count (RAC) and mean linear intercept (MLI) were measured as parameters of alveolarization. Apoptosis was evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method and cleaved caspase-3 immunohistochemistry. Serum HSP70 levels in preterm humans treated with oxygen were measured by enzyme-linked immunosorbent assay.

Results

GGA administration enhanced the HSP70 expression to two-fold compared with normoxia-exposed and vehicle-treated mice. Hyperoxia reduced HSP70 expression, whereas GGA abrogated the effects. Hyperoxia-exposed mice exhibited more apoptotic cells in lung parenchyma and a more simplified alveolar structure with less RAC and larger MLI than normoxia-exposed mice. GGA suppressed the increase in apoptotic cells and the structural changes of the lungs induced by hyperoxia. Serum HSP70 levels of preterm human infants gradually decreased with age.

Conclusions

GGA may attenuate hyperoxic injury in neonatal lungs and thereby may prevent the development of BPD.

The Influence of Hyperoxia On Heat Shock Proteins Expression and Nitric Oxide Synthase Activity – the Review

Any stay in an environment with an increased oxygen content (a higher oxygen partial pressure, pO2) and an increased pressure (hyperbaric conditions) leads to an intensification of oxidative stress. Reactive oxygen species (ROS) damage the molecules of proteins, nucleic acids, cause lipid oxidation and are engaged in the development of numerous diseases, including diseases of the circulatory system, neurodegenerative diseases, etc. There are certain mechanisms of protection against unfavourable effects of oxidative stress. Enzymatic and non-enzymatic systems belong to them. The latter include, among others, heat shock proteins (HSP). Their precise role and mechanism of action have been a subject of intensive research conducted in recent years. Hyperoxia and hyperbaria also have an effect on the expression and activity of nitrogen oxide synthase (NOS). Its product - nitrogen oxide (NO) can react with reactive oxygen species and contribute to the development of nitrosative stress. NOS occurs as isoforms in various tissues and exhibit different reactions to the discussed factors. The authors have prepared a brief review of research determining the effect of hyperoxia and hyperbaria on HSP expression and NOS activity.

Modulation of Alloimmunity by Heat Shock Proteins

The immunological mechanisms that evolved for host defense against pathogens and injury are also responsible for transplant rejection. Host rejection of foreign tissue was originally thought to be mediated mainly by T cell recognition of foreign MHC alleles. Management of solid organ transplant rejection has thus focused mainly on inhibition of T cell function and matching MHC alleles between donor and host. Recently, however, it has been demonstrated that the magnitude of the initial innate immune responses upon transplantation has a decisive impact on rejection. The exact mechanisms underlying this phenomenon have yet to be characterized. Ischemic cell death and inflammation that occur upon transplantation are synonymous with extracellular release of various heat shock proteins (Hsps), many of which have been shown to have immune-modulatory properties. Here, we review the impact of Hsps upon alloimmunity and discuss the potential use of Hsps as accessory agents to improve solid organ transplant outcomes.

Geranylgeranylacetone alleviates radiation-induced lung injury by inhibiting epithelial-to-mesenchymal transition signaling

Radiation-induced lung injury (RILI) involves pneumonitis and fibrosis, and results in pulmonary dysfunction. Moreover, RILI can be a fatal complication of thoracic radiotherapy. The present study investigated the protective effect of geranylgeranlyacetone (GGA), an inducer of heat shock protein (HSP)70, on RILI using a C57BL/6 mouse model of RILI developing 6 months subsequent to exposure to 12.5 Gy thoracic radiation. GGA was administered 5 times orally prior and subsequent to radiation exposure, and the results were assessed by histological analysis and western blotting. The results show that late RILI was alleviated by GGA treatment, possibly through the suppression of epithelial‑to‑mesenchymal transition (EMT) marker expression. Based on histological examination, orally administered GGA during the acute phase of radiation injury not only significantly inhibited pro‑surfactant protein C (pro‑SPC) and vimentin expression, but also preserved E‑cadherin expression 6 months after irradiation‑induced injury of the lungs. GGA induced HSP70 and inhibited EMT marker expression in L132 human lung epithelial cells following IR. These data suggest that the prevention of EMT signaling is a key cytoprotective effect in the context of RILI. Thus, HSP70‑inducing drugs, such as GGA, could be beneficial for protection against RILI.

Hsp70 Knockdown by siRNA Decreased Collagen Production in Keloid Fibroblasts

PURPOSE

There are currently no consistently effective treatments for the excessive collagen produced by keloid fibroblasts. Previously, we reported that heat shock protein 70 (Hsp70) is up-regulated in keloid fibroblasts and keloid tissue. We, therefore, investigated whether Hsp70 is related to excessive collagen production in keloid fibroblasts.

MATERIALS AND METHODS

We inhibited Hsp70 in keloid fibroblasts by RNA interference and examined the resulting collagen expression. Thus, we selected small interfering RNAs (siRNAs) specific for human Hsp70, transfected them into keloid fibroblasts, and evaluated the resulting phenotypes and protein production using real-time polymerase chain reaction (PCR), Western blot, and a collagen assay.

RESULTS

The siRNAs dramatically suppressed Hsp70 mRNA expression, resulting in a decrease in collagen production in the keloid fibroblasts compared with controls. The siRNAs did not influence the viability of the keloid fibroblasts.

CONCLUSION

Hsp70 overexpression likely plays an important role in the excessive collagen production by keloid fibroblasts. RNA interference has therapeutic potential for the treatment of keloids.

Analysis of heat shock protein 70 gene polymorphisms Mexican patients with idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease of unknown etiology. Genetic variation within different major histocompatibility complex (MHC) loci contributes to the susceptibility to IPF. The effect of 70 kDa heat shock proteins (HSP70) gene polymorphisms in the susceptibility to IPF is unknown. The aim of this study was to explore the association between HSP70 polymorphisms and IPF susceptibility in the Mexican population.

Methods

Four HSP70 single nucleotide polymorphisms (SNPs) were evaluated using real time PCR assays in 168 IPF patients and 205 controls: +2763 C>T of HSPA1L (rs2075800), +2437 of HSP HSPA1L A>G (rs2227956), +190 of HSPA1A G>C (rs1043618) and +1267 of HSPA1B G>A (rs1061581).

Results

The analysis of the recessive model revealed a significant decrease in the frequency of the genotype HSPA1B AA (rs1061581) in IPF patients (OR = 0.27, 95 % CI = 0.13–0.57, Pc = 0.0003) when compared to controls. Using a multivariate logistic regression analysis in a codominant model the HSPA1B (rs1061581) GA and AA genotypes were associated with a lower risk of IPF compared with GG (OR = 0.22, 95 % CI = 0.07–0.65; p = 0.006 and OR = 0.17, 95 % CI = 0.07–0.41; p = <0.001). Similarly, HSPA1L (rs2227956) AG genotype (OR = 0.34, 95 % CI = 0.12–0.99; p = 0.04) and the dominant model AG + GG genotypes were also associated with a lower risk of IPF (OR = 0.24, 95 % CI = 0.08–0.67; p = 0.007). In contrast, the HSPA1L (rs2075800) TT genotype was associated with susceptibility to IPF (OR = 2.52, 95 % CI = 1.32–4.81; p = 0.005).

Conclusion

Our findings indicate that HSPA1B (rs1061581), HSPA1L (rs2227956) and HSPA1 (rs1043618) polymorphisms are associated with a decreased risk of IPF.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0127-7) contains supplementary material, which is available to authorized users.

STAT-3 contributes to pulmonary fibrosis through epithelial injury and fibroblast-myofibroblast differentiation

Lung fibrosis is the hallmark of the interstitial lung diseases. Alveolar epithelial cell (AEC) injury is a key step that contributes to a profibrotic microenvironment. Fibroblasts and myofibroblasts subsequently accumulate and deposit excessive extracellular matrix. In addition to TGF-β, the IL-6 family of cytokines, which signal through STAT-3, may also contribute to lung fibrosis. In the current manuscript, the extent to which STAT-3 inhibition decreases lung fibrosis is investigated. Phosphorylated STAT-3 was elevated in lung biopsies from patients with idiopathic pulmonary fibrosis and bleomycin (BLM)-induced fibrotic murine lungs. C-188-9, a small molecule STAT-3 inhibitor, decreased pulmonary fibrosis in the intraperitoneal BLM model as assessed by arterial oxygen saturation (control, 84.4 ± 1.3%; C-188-9, 94.4 ± 0.8%), histology (Ashcroft score: untreated, 5.4 ± 0.25; C-188-9, 3.3 ± 0.14), and attenuated fibrotic markers such as diminished α-smooth muscle actin, reduced collagen deposition. In addition, C-188-9 decreased the expression of epithelial injury markers, including hypoxia-inducible factor-1α (HIF-1α) and plasminogen activator inhibitor-1 (PAI-1). In vitro studies show that inhibition of STAT-3 decreased IL-6- and TGF-β-induced expression of multiple genes, including HIF-1α and PAI-1, in AECs. Furthermore, C-188-9 decreased fibroblast-to-myofibroblast differentiation. Finally, TGF-β stimulation of lung fibroblasts resulted in SMAD2/SMAD3-dependent phosphorylation of STAT-3. These findings demonstrate that STAT-3 contributes to the development of lung fibrosis and suggest that STAT-3 may be a therapeutic target in pulmonary fibrosis.

Geranylgeranylacetone attenuates hepatic fibrosis by increasing the expression of heat shock protein 70

Increasing evidence has demonstrated that the heat shock protein 70 (HSP70) gene may be closely associated with tissue fibrosis; however, the association between HSP70 and liver fibrosis remains to be fully elucidated. The present study hypothesized that geranylgeranylacetone (GGA) exerts beneficial effects on liver fibrosis though upregulation of the expression of HSP70. Liver fibrosis was induced in rats using carbon tetrachloride (CCl₄). The rats were subsequently divided into three groups: Control group, CCl₄ model group and CCl₄ model + GGA group. Liver fibrosis in the rats was evaluated using hematoxylin and eosin staining, Masson's trichrome staining and Sirius red staining. The levels of serum alanine aminotransferase, aspartate aminotransferase and total bilirubin were determined using an automated biochemistry analyzer. The levels of total hepatic hydroxyproline were also determined. The expression levels of α-smooth muscle actin (α-SMA) and transforming growth factor-β1 (TGF-β1) were determined using immunofluorescence staining and western blotting, and the protein expression levels of HSP70 were determined using western blotting. The CCl₄-induced rats exhibited liver fibrosis, increased hydroxyproline content, impaired liver function, upregulated expression levels of the α-SMA and TGF-β1 pro-fibrogenic proteins, and increased expression of HSP70, compared with the control group. These changes were attenuated by treatment with GGA. These results demonstrated that GGA exerted beneficial effects in CCl₄-induced liver fibrosis via upregulating the expression of HSP70.

The exacerbating roles of CCAAT/enhancer-binding protein homologous protein (CHOP) in the development of bleomycin-induced pulmonary fibrosis and the preventive effects of tauroursodeoxycholic acid (TUDCA) against pulmonary fibrosis in mice

The purpose of this study was to evaluate the role of CCAAT/enhancer-binding protein homologous protein (CHOP), an important transcription factor that regulates the inflammatory reaction during the endoplasmic reticulum (ER) stress response, in the development of pulmonary fibrosis induced by bleomycin (BLM) in mice. An intratracheal injection of BLM transiently increased the expression of CHOP mRNA and protein in an early phase (days 1 and 3) in mice lungs. BLM-induced pulmonary fibrosis was significantly attenuated in Chop gene deficient (Chop KO) mice, compared with wild-type (WT) mice. Furthermore, the inflammatory reactions evaluated by protein concentration, the total number of leucocytes and neutrophils in the bronchoalveolar lavage fluid (BALF), the mRNA expression of interleukin 1b and caspase 11, and the apoptotic cell death were suppressed in Chop KO mice compared with those in WT mice. In addition, administration of tauroursodeoxycholic acid (TUDCA), a pharmacological agent that can inhibit CHOP expression, inhibited the BLM-induced pulmonary fibrosis and inflammation, and the increase in Chop mRNA expression in WT mice in a dose-dependent manner. These results suggest that the ER stress-induced transcription factor, CHOP, at least in part, plays an important role in the development of BLM-induced pulmonary fibrosis in mice, and that the inhibition of CHOP expression by a pharmacological agent, such as TUDCA, may be a promising strategy for the prevention of pulmonary fibrosis.

New treatment and markers of prognosis for idiopathic pulmonary fibrosis: lessons learned from translational research

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease with increasing prevalence, high mortality rates and poor treatment options. The diagnostic process is complex and often requires an interdisciplinary approach between different specialists. Information gained over the past 10 years of intense research resulted in improved diagnostic algorithms, a better understanding of the underlying pathogenesis and the development of new therapeutic options. Specifically, the change from the traditional concept that viewed IPF as a chronic inflammatory disorder to the current belief that is primarily resulting from aberrant wound healing enabled the identification of novel treatment targets. This increased the clinical trial activity dramatically and resulted in the approval of the first IPF-specific therapy in many countries. Still, the natural history and intrinsic behavior of IPF are very difficult to predict. There is an urgent need for new therapies and also for development and validation of prognostic markers that predict disease progression, survival and also response to antifibrotic drugs. This review provides an up to date summary of the most relevant clinical trials, novel therapeutic drug targets and outlines a spectrum of potential prognostic biomarkers for IPF.

Interleukin-33 potentiates bleomycin-induced lung injury

The mechanisms of interstitial lung disease (ILD) remain incompletely understood, although recent observations have suggested an important contribution by IL-33. Substantial elevations in IL-33 expression were found in the lungs of patients with idiopathic pulmonary fibrosis and scleroderma lung disease, as well as in the bleomycin injury mouse model. Most of the observed IL-33 expression was intracellular and intranuclear, suggesting involvement of the full-length (fl) protein, but not of the proteolytically processed mature IL-33 cytokine. The effects of flIL-33 on mouse lungs were assessed independently and in combination with bleomycin injury, using recombinant adenovirus-mediated gene delivery. Bleomycin-induced changes were not affected by gene deficiency of the IL-33 receptor T1/ST2. Combined flIL-33 expression and bleomycin injury exerted a synergistic effect on pulmonary lymphocyte and collagen accumulation, which could be explained by synergistic regulation of the cytokines transforming growth factor-β, IL-6, monocyte chemotactic protein-1, macrophage inflammatory protein\x{2013}1α, and tumor necrosis factor-α. By contrast, no increase in the levels of the Th2 cytokines IL-4, IL-5, or IL-13 was evident. Moreover, flIL-33 was found to increase the expression of several heat shock proteins (HSPs) significantly, and in particular HSP70, which is known to be associated with ILD. Thus, flIL-33 is a synergistic proinflammatory and profibrotic regulator that acts by stimulating the expression of several non-Th2 cytokines, and activates the expression of HSP70.

Plasma membranes as heat stress sensors: from lipid-controlled molecular switches to therapeutic applications

The classic heat shock (stress) response (HSR) was originally attributed to protein denaturation. However, heat shock protein (Hsp) induction occurs in many circumstances where no protein denaturation is observed. Recently considerable evidence has been accumulated to the favor of the "Membrane Sensor Hypothesis" which predicts that the level of Hsps can be changed as a result of alterations to the plasma membrane. This is especially pertinent to mild heat shock, such as occurs in fever. In this condition the sensitivity of many transient receptor potential (TRP) channels is particularly notable. Small temperature stresses can modulate TRP gating significantly and this is influenced by lipids. In addition, stress hormones often modify plasma membrane structure and function and thus initiate a cascade of events, which may affect HSR. The major transactivator heat shock factor-1 integrates the signals originating from the plasma membrane and orchestrates the expression of individual heat shock genes. We describe how these observations can be tested at the molecular level, for example, with the use of membrane perturbers and through computational calculations. An important fact which now starts to be addressed is that membranes are not homogeneous nor do all cells react identically. Lipidomics and cell profiling are beginning to address the above two points. Finally, we observe that a deregulated HSR is found in a large number of important diseases where more detailed knowledge of the molecular mechanisms involved may offer timely opportunities for clinical interventions and new, innovative drug treatments. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.

IL-10 is significantly involved in HSP70-regulation of experimental subretinal fibrosis

Subretinal fibrosis is directly related to severe visual loss, especially if occurs in the macula, and is frequently observed in advanced age-related macular degeneration and other refractory eye disorders such as diabetic retinopathy and uveitis. In this study, we analyzed the immunosuppressive mechanism of subretinal fibrosis using the novel animal model recently demonstrated. Both TLR2 and TLR4 deficient mice showed significant enlargement of subretinal fibrotic area as compared with wild-type mice. A single intraocular administration of heat shock protein 70 (HSP70), which is an endogenous ligand for TLR2 and TLR4, inhibited subretinal fibrosis in wild-type mice but not in TLR2 and TLR4-deficient mice. Additionally, HSP70 induced IL-10 production in eyes from wild-type mice but was impaired in both TLR2- and TLR4-deficient mice, indicating that HSP70-TLR2/TLR4 axis plays an immunomodulatory role in subretinal fibrosis. Thus, these results suggest that HSP70-TLR2/TLR4 axis is a new therapeutic target for subretinal fibrosis due to prognostic CNV.

Gefitinib, but not erlotinib, is a possible inducer of Fra-1-mediated interstitial lung disease

Gefitinib is an anticancer drug developed to inhibit the tyrosine kinase activity of the epidermal growth factor receptor (EGFR). Two structurally-related EGFR tyrosine kinase inhibitors, gefitinib (Iressa) and erlotinib (Tarceva), are used as oral chemotherapy by patients with non-small-cell lung cancer. Immediately after introduction of gefitinib to clinical practice, interstitial lung disease was identified as a life-threatening adverse effect, although this condition can be well managed. It is still unclear whether gefitinib and other EGFR inhibitors induce similar adverse effects in lung. We previously established mouse models of interstitial lung disease in which gefitinib induces expression of Fosl1 (which encodes the AP-1 transcription factor Fra-1) in the presence of exogenous or endogenous Toll-like receptor ligands, leading to abnormal cytokine and chemokine expression. Here, we compared and monitored the effects of EGFR inhibitors gefitinib, erlotinib and AG1517 (PD153035) on the mRNA expression levels of Fosl1, Tnf and Ccl2. Unexpectedly, gefitinib, but not the other tyrosine kinase inhibitors, elicited the Fosl1 expression profile proposed to be predictive of interstitial lung disease, suggesting that gefitinib-induced interstitial lung disease is an off-target effect not elicited by erlotinib.