Prevention of bleomycin-induced pulmonary fibrosis by vaccination with the Tocilizumab mimotope

Mimotope, a kind of peptide vaccine, is developed to bind natural receptor and inhibit the downstream signaling. We have demonstrated that the vaccination of Tocilizumab mimotopes could alleviate the renal fibrosis by interfering with both IL-6 and ferroptosis signaling. However, the effect of the vaccination of Tocilizumab mimotopes on the fibroblast was not investigated in previous study. Thus, we sought to explore the changes in the fibroblast induced by the Tocilizumab mimotopes vaccination. Bleomycin instillation was performed to construct the pulmonary fibrosis model after the immunization of Tocilizumab mimotopes. Lung histological analysis showed that the Tocilizumab mimotopes could significantly reduce the maladaptive repairment and abnormal remodeling. Immunoblotting assay and fluorescence staining showed that Immunization with the Tocilizumab mimotopes reduces the accumulation of fibrosis-related proteins. High level of lipid peroxidation product was observed in the animal model, while the Tocilizumab mimotopes vaccination could reduce the generation of lipid peroxidation product. Mechanism analysis further showed that Nrf-2 signaling, but not GPX-4 and FSP-1 signaling, was upregulated, and reduced the lipid peroxidation. Our results revealed that in the BLM-induced pulmonary fibrosis, high level of lipid peroxidation product was significantly accumulation in the lung tissues, which might lead to the occurrence of ferroptosis. The IL-6 pathway block therapy could inhibit lipid peroxidation product generation in the lung tissues by upregulating the Nrf-2 signaling, and further alleviate the pulmonary fibrosis.

Macrophage expressed tartrate-resistant acid phosphatase 5 promotes pulmonary fibrosis progression

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disorder involving scarring of pulmonary tissue and a subsequent decrease in respiratory capacity, ultimately resulting in death. Tartrate resistant acid phosphatase 5 (ACP5) plays a role in IPF but the exact mechanisms are yet to be elucidated. In this study, we have utilized various perturbations of the bleomycin mouse model of IPF including genetic knockout, RANKL inhibition, and macrophage adoptive transfer to further understand ACP5's role in pulmonary fibrosis. Genetic ablation of Acp5 decreased immune cell recruitment to the lungs and reduced the levels of hydroxyproline (reflecting extracellular matrix-production) as well as histological damage. Additionally, gene expression profiling of murine lung tissue revealed downregulation of genes including Ccl13, Mmp13, and Il-1α that encodes proteins specifically related to immune cell recruitment and macrophage/fibroblast interactions. Furthermore, antibody-based neutralization of RANKL, an important inducer of Acp5 expression, reduced immune cell recruitment but did not decrease fibrotic lung development. Adoptive transfer of Acp5-/- bone marrow-derived monocyte (BMDM) macrophages 7 or 14 days after bleomycin administration resulted in reductions of cytokine production and decreased levels of lung damage, compared to adoptive transfer of WT control macrophages. Taken together, the data presented in this study suggest that macrophage derived ACP5 plays an important role in development of pulmonary fibrosis and could present a tractable target for therapeutic intervention in IPF.

Calcium transferring from ER to mitochondria via miR-129/ITPR2 axis controls cellular senescence in vitro and in vivo

Senescent cells are known to be accumulated in aged organisms. Although the two main characteristics, cell cycle arrest (for dividing cells) and secretion of senescence-associated secretory phenotype (SASP) factors, have been well described, the lack of sufficient senescent markers and incomplete understanding of mechanisms have limited the progress of the anti-senescence field. Calcium transferred from the endoplasmic reticulum (ER) via inositol 1, 4, 5-trisphosphate receptor type 2 (ITPR2) to mitochondria has emerged as a key player during cellular senescence and aging. However, the internal regulatory mechanisms, particularly those of endogenous molecules, remain only partially understood. Here we identified miRNA-129 (miR-129) as a direct repressor of ITPR2. Interestingly, miR-129 controlled a cascade of intracellular calcium signaling, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), DNA damage, and consequently cellular senescence through ITPR2 and mitochondrial calcium uniporter (MCU). In addition, miR-129 was repressed in different senescence models and delayed bleomycin-induced cellular senescence. Importantly, intraperitoneal injection of miR-129 partly postponed bleomycin-accelerated lung aging and natural aging markers as well as reduced immunosenescence markers in mice. Altogether, these findings demonstrated that miR-129 regulated cellular senescence and aging markers via intracellular calcium signaling by directly targeting ITPR2.

Bleomycin-treated myoblasts undergo p21-associated cellular senescence and have severely impaired differentiation

As we age, the ability to regenerate and repair skeletal muscle damage declines, partially due to increasing dysfunction of muscle resident stem cells-satellite cells (SC). Recent evidence implicates cellular senescence, which is the irreversible arrest of proliferation, as a potentiator of SC impairment during aging. However, little is known about the role of senescence in SC, and there is a large discrepancy in senescence classification within skeletal muscle. The purpose of this study was to develop a model of senescence in skeletal muscle myoblasts and identify how common senescence-associated biomarkers respond. Low-passage C2C12 myoblasts were treated with bleomycin or vehicle and then evaluated for cytological and molecular senescence markers, proliferation status, cell cycle kinetics, and differentiation potential. Bleomycin treatment caused double-stranded DNA breaks, which upregulated p21 mRNA and protein, potentially through NF-κB and senescence-associated super enhancer (SASE) signaling (p < 0.01). Consequently, cell proliferation was abruptly halted due to G2/M-phase arrest (p < 0.01). Bleomycin-treated myoblasts displayed greater senescence-associated β-galactosidase staining (p < 0.01), which increased over several days. These myoblasts remained senescent following 6 days of differentiation and had significant impairments in myotube formation (p < 0.01). Furthermore, our results show that senescence can be maintained despite the lack of p16 gene expression in C2C12 myoblasts. In conclusion, bleomycin treatment provides a valid model of damage-induced senescence that was associated with elevated p21, reduced myoblast proliferation, and aberrant cell cycle kinetics, while confirming that a multi-marker approach is needed for the accurate classification of senescence within skeletal muscle.

Inhibition of bleomycin-induced pulmonary fibrosis in SD rats by sea cucumber peptides

BACKGROUND

Pulmonary fibrosis (PF) is the terminal manifestation of a type of pulmonary disease, which seriously affects the respiratory function of the body, and with no effective cure for treatment. This study evaluated the effect of sea cucumber peptides (SCP) on bleomycin-induced SD rat PF.

RESULTS

SCP can inhibit the PF induced by bleomycin. PF and SCP did not affect the food intake of rats, but PF reduced the body weight of rats, and SCP could improve the weight loss. SCP reduced lung index in PF rats in a dose-dependent manner. SCP significantly reduced IL-1β, IL-6, TNF-α, α-SMA and VIM expression levels in lung tissue (P < 0.05), significantly decreased TGF-β1 expression level in serum (P < 0.01) and the LSCP group and MSCP group had better inhibitory effects on PF than the HSCP group. Histomorphological results showed that SCP could ameliorate the structural damage of lung tissue, alveolar wall rupture, inflammatory cell infiltration, fibroblast proliferation and deposition of intercellular matrix and collagen fibers caused by PF. The improvement effect of the MSCP group was the most noteworthy in histomorphology. Metabolomics results showed that SCP significantly downregulated catechol, N-acetyl-l-histidine, acetylcarnitine, stearoylcarnitine, d-mannose, l-threonine, l-alanine, glycine, 3-guanidinopropionic acid, prostaglandin D2 and embelic acid d-(-)-β-hydroxybutyric acid expression levels in lung tissue.

CONCLUSION

SCP ameliorate bleomycin-induced SD rat PF. KEGG pathway analysis proved that SCP intervened in PF mainly via the lysosome pathway, with d-mannose as the key factor. © 2023 Society of Chemical Industry.

Attenuation of fibroblast activation and fibrosis by adropin in systemic sclerosis

Fibrotic diseases impose a major socioeconomic challenge on modern societies and have limited treatment options. Adropin, a peptide hormone encoded by the energy homeostasis-associated (ENHO) gene, is implicated in metabolism and vascular homeostasis, but its role in the pathogenesis of fibrosis remains enigmatic. Here, we used machine learning approaches in combination with functional in vitro and in vivo experiments to characterize adropin as a potential regulator involved in fibroblast activation and tissue fibrosis in systemic sclerosis (SSc). We demonstrated consistent down-regulation of adropin/ENHO in skin across multiple cohorts of patients with SSc. The prototypical profibrotic cytokine TGFβ reduced adropin/ENHO expression in a JNK-dependent manner. Restoration of adropin signaling by therapeutic application of bioactive adropin34-76 peptides in turn inhibited TGFβ-induced fibroblast activation and fibrotic tissue remodeling in primary human dermal fibroblasts, three-dimensional full-thickness skin equivalents, mouse models of bleomycin-induced pulmonary fibrosis and sclerodermatous chronic graft-versus-host-disease (sclGvHD), and precision-cut human skin slices. Knockdown of GPR19, an adropin receptor, abrogated the antifibrotic effects of adropin in fibroblasts. RNA-seq demonstrated that the antifibrotic effects of adropin34-76 were functionally linked to deactivation of GLI1-dependent profibrotic transcriptional networks, which was experimentally confirmed in vitro, in vivo, and ex vivo using cultured human dermal fibroblasts, a sclGvHD mouse model, and precision-cut human skin slices. ChIP-seq confirmed adropin34-76-induced changes in TGFβ/GLI1 signaling. Our study characterizes the TGFβ-induced down-regulation of adropin/ENHO expression as a potential pathomechanism of SSc as a prototypical systemic fibrotic disease that unleashes uncontrolled activation of profibrotic GLI1 signaling.

High S100A9 level predicts poor survival, and the S100A9 inhibitor paquinimod is a candidate for treating idiopathic pulmonary fibrosis

BACKGROUND

S100A9 is a damage-associated molecular pattern protein that may play an important role in the inflammatory response and fibrotic processes. Paquinimod is an immunomodulatory compound that prevents S100A9 activity. Its safety and pharmacokinetics have been confirmed in human clinical trials. In this study, we investigated the effects of paquinimod in preventing the development of lung fibrosis in vivo and examined the prognostic values of circulatory and lung S100A9 levels in patients with idiopathic pulmonary fibrosis (IPF).

METHODS

The expression and localisation of S100A9 and the preventive effect of S100A9 inhibition on fibrosis development were investigated in a mouse model of bleomycin-induced pulmonary fibrosis. In this retrospective cohort study, the S100A9 levels in the serum and bronchoalveolar lavage fluid (BALF) samples from 76 and 55 patients with IPF, respectively, were examined for associations with patient survival.

RESULTS

S100A9 expression was increased in the mouse lungs, especially in the inflammatory cells and fibrotic interstitium, after bleomycin administration. Treatment with paquinimod ameliorated fibrotic pathological changes and significantly reduced hydroxyproline content in the lung tissues of mice with bleomycin-induced pulmonary fibrosis. Additionally, we found that paquinimod reduced the number of lymphocytes and neutrophils in BALF and suppressed endothelial-mesenchymal transition in vivo. Kaplan-Meier curve analysis and univariate and multivariate Cox hazard proportion analyses revealed that high levels of S100A9 in the serum and BALF were significantly associated with poor prognoses in patients with IPF (Kaplan-Meier curve analysis: p=0.037 (serum) and 0.019 (BALF); multivariate Cox hazard proportion analysis: HR=3.88, 95% CI=1.06 to 14.21, p=0.041 (serum); HR=2.73, 95% CI=1.05 to 7.10, p=0.039 (BALF)).

CONCLUSIONS

The present results indicate that increased S100A9 expression is associated with IPF progression and that the S100A9 inhibitor paquinimod is a potential treatment for IPF.

Time course of histopathology of bleomycin-induced pulmonary fibrosis using an intratracheal sprayer in mice

Idiopathic pulmonary fibrosis (IPF) is a poor prognosis disease that affects approximately 5 million people worldwide, and the detailed mechanisms underlying the pathogenesis of IPF remain unclear. Bleomycin-induced pulmonary fibrosis has been widely used as a representative animal model of IPF that induces fibrosis in lung tissue. The lungs of rodent consist of five lobes and each bronchus enters each lobe of the lung at a different bifurcation angle, path length, and diameter. The method of administration of bleomycin is considered as important thing to establish appropriate animal models. We conducted a time-dependent histopathological study to examine how pulmonary fibrosis develops in each lung lobe when bleomycin was intratracheally sprayed in ICR mice. And we then explored the suitable points for evaluation of anti-fibrotic agents in this model. As a result, we found that homogeneous fibrosis was induced in the 5 lobes of the lungs following initial inflammation. The expression of transforming growth factor (TGF)-β1 and phospho-Smad2 (pSmad2) was observed from Day 1, and their positivity increased until Day 21. In conclusion, we have observed a detailed time course of histological changes in bleomycin-induced pulmonary fibrosis in ICR mice using the aerosolization technique. We found that our protocol can induce a highly homogeneous lesion in the lung and that the most suitable time point to assess anti-fibrotic agents is 14 days after treatment in this model.

Investigation of miR-26b and miR-27b expressions and the effect of quercetin on fibrosis in experimental pulmonary fibrosis

In this study, investigation of the effects of Quercetin on Bleomycin-induced pulmonary fibrosis and fibrosis-associated molecules miR-26b and miR-27b was aimed. Control group was given 10% saline on the 0th day, and saline was administered for 21 days starting from the 8th day. Group 2 was given 50 mg/kg Quercetin for 21 days starting from the 8th day. Group 3 was given 10 mg/kg Bleomycin Sulfate on day 0, and sacrificed on the 22nd and 29th day. Group 4 was given 10 mg/kg Bleomycin Sulfate on the 0th day, and was given 50 mg/kg Quercetin for 14 days, and 21 days starting from day 8. Lung tissues were examined using light and electron microscopic, immunohistochemical and molecular biological methods. Injury groups revealed impaired alveolar structure, collagen accumulation and increased inflammatory cells in interalveolar septum. Fibrotic response was decreased and the alveolar structure was improved with Quercetin treatment. α-SMA expressions were higher in the injury groups, but lower in the treatment groups compared to the injury groups. E-cadherin expressions were decreased in the injury groups and showed stronger immunoreactivity in the treatment groups compared to the injury groups. miR-26b and miR-27b expressions were lower in the injury groups than the control groups, and higher in the treatment groups than the injury groups. Quercetin can be considered as a new treatment agent in the idiopathic pulmonary fibrosis, since it increases the expression levels of miR-26b and miR-27b which decrease in fibrosis, and has therapeutic effects on the histopathological changes.

Transcriptional Levels of Intercellular Junction Proteins in an Alveolar Epithelial Cell Line Exposed to Irradiation or Bleomycin

We performed a comparative study of the effects of X-ray irradiation and bleomycin on the mRNA levels of E-cadherin and tight junction proteins (claudin-3, claudin-4, claudin-18, ZO-2, and occludin) in an alveolar epithelial cell line L2. Irradiation decreased claudin-4 levels and increased occludin levels, while the levels of other mRNAs remained unchanged. Bleomycin increased the expression levels of all proteins examined except claudin-3. Irradiation and bleomycin have different effects on the expression level of intercellular junction proteins, indicating different reactions triggered in alveolar epithelial cells and a great prospects of further comparative studies.

Therapeutic effect of sodium alginate on bleomycin, etoposide and cisplatin (BEP)-induced reproductive toxicity by inhibiting nitro-oxidative stress, inflammation and apoptosis

Impaired spermatogenesis and male infertility are common consequences of chemotherapy drugs used in patients with testicular cancer. The present study investigated the effects of sodium alginate (NaAL) on testicular toxicity caused by bleomycin, etoposide, and cisplatin (BEP). Rats in group 1 received normal saline, while groups 2 and 3 were treated with 25 and 50 mg/kg of NaAL, respectively. Group 4 was treated with a 21-day cycle of BEP (0.5 mg/kg bleomycin, 5 mg/kg etoposide, and 1 mg/kg cisplatin), and groups 5 and 6 received BEP regimen plus 25 and 50 mg/kg of NaAL, respectively. Then, sperm parameters, testosterone levels, testicular histopathology and stereological parameters, testicular levels of malondialdehyde (MDA), nitric oxide (NO), and total antioxidant capacity (TAC), and the expression of apoptosis-associated genes including Bcl2, Bax, Caspase3, p53, and TNF-α were evaluated. Our findings revealed that NaAL improved sperm parameters, testosterone levels, histopathology, and stereology parameters in BEP-administrated rats. NaAL also improved testis antioxidant status by enhancing TAC and ameliorating MDA and NO. Further, modifications to the expression of Bcl2, Bax, Caspase3, p53, and TNF-α suggested that NaAL alleviated BEP-induced apoptosis and inflammation. Collectively, NaAL protects rats' testes against BEP-evoked toxicity damage through the modulation of nitro-oxidative stress, apoptosis, and inflammation.

Hydrogen sulfide inhibits alveolar type II cell senescence and limits pulmonary fibrosis via promoting MDM2-mediated p53 degradation

AIM

Senescence of alveolar type II (AT2) cells is an important driver of pulmonary fibrosis. This study aimed to investigate whether and how dysregulation of hydrogen sulfide (H2 S) production affected AT2 cell senescence, and then explored the effect of H2 S on the communication between AT2 and fibroblasts.

METHODS

ICR mice were intratracheally administered with bleomycin (3 mg/kg). Sodium hydrosulfide (NaHS, 28 μmol/kg/d) was intraperitoneally injected for 2 weeks. The H2 S-generating enzyme cystathionine-β-synthase (CBS) knockout heterozygous (CBS+/- ) mice were used as a low H2 S production model.

RESULTS

Analysis of microarray datasets revealed downregulation of H2 S-generating enzymes in lung tissues of patients with pulmonary fibrosis. Decreased H2 S production was correlated with higher levels of cell senescence markers p53 and p21 in bleomycin-induced lung fibrosis. CBS+/- mice exhibited increased levels of p53 and p21. The numbers of AT2 cells positive for p53 and p21 were increased in CBS+/- mice as compared to control mice. H2 S donor NaHS attenuated bleomycin-induced AT2 cell senescence both in vivo and in vitro. H2 S donor suppressed bleomycin-induced senescence-associated secretory phenotype (SASP) of AT2 cells via inhibiting p53/p21 pathway, consequently suppressing proliferation and myofibroblast transdifferentiation of fibroblasts. Mechanically, H2 S suppressed p53 expression by enhancing the mouse double-minute 2 homologue (MDM2)-mediated ubiquitination and degradation of p53.

CONCLUSION

H2 S inactivated p53-p21 pathway, consequently suppressing AT2 cell senescence as well as cell communication between senescent AT2 cells and fibroblasts. Aberrant H2 S synthesis may contribute to the development of pulmonary fibrosis through promoting the activation loop involving senescent AT2 cells and activated fibroblasts.

miR-302d Targeting of CDKN1A Regulates DNA Damage and Steroid Hormone Secretion in Bovine Cumulus Cells

(1) Background: DNA damage in cumulus cells hinders oocyte maturation and affects steroid hormone secretion. It is crucial to identify the key factors that regulate cellular DNA damage and steroid hormone secretion. (2) Methods: Treatment of bovine cumulus cells with bleomycin to induce DNA damage. The effects of DNA damage on cell biology were determined by detecting changes in DNA damage degree, cell cycle, viability, apoptosis, and steroid hormones. It was verified that mir-302d targeted regulation of CDKN1A expression, and then affected DNA damage and steroid hormone secretion in cumulus cells. (3) Results: Bleomycin induced increased DNA damage, decreased G1-phase cells, increased S-phase cells, inhibited proliferation, promoted apoptosis, affected E2 and P4 secretion, increased CDKN1A expression, and decreased miR-302d expression. Knockdown of CDKN1A reduced DNA damage, increased G1-phase cells, decreased G2-phase cells, promoted proliferation, inhibited apoptosis, increased E2 and P4 secretion, and increased the expression of BRCA1, MRE11, ATM, CDK1, CDK2, CCNE2, STAR, CYP11A1, and HSD3B1. The expression of RAD51, CCND1, p53, and FAS was decreased. Overexpression of CDKN1A resulted in the opposite results. miR-302d targets CDKN1A expression to regulate DNA damage and then affects the cell cycle, proliferation, apoptosis, steroid hormone secretion, and the expression of related genes. (4) Conclusions: miR-302d and CDKN1A were candidate molecular markers for the diagnosis of DNA damage in bovine cumulus cells.

Saikosaponin-d regulates angiogenesis in idiopathic pulmonary fibrosis through angiopoietin/Tie-2 pathway

OBJECTIVE

Idiopathic pulmonary fibrosis (IPF) is considered as a chronic interstitial lung disease with underlying mechanism of IPF remaining unclear, while there are no definitive treatment options. In recent years, scientists have gradually paid attention to the influence of angiogenesis on IPF. Because IPF is a progressive with microvascular remodeling disorder, scientists have postulated that angiogenesis may also be one of the initiating and contributing factors of the disease. Bupleurum is a common natural Chinese herbal medicine with antibacterial, anti-inflammatory, anti-tumor and other pharmacological effects. As the most important active monomer of Bupleurum, Saikosaponin-d (SSd) is a new discovery with anti-pulmonary fibrosis (PF) activity. This study attempts to investigate the role of SSd in the interference of PF through regulation of angiogenesis in IPF through Angiopoietin (Angpt) /Tie receptor 2 (Tie2) pathway.

METHODS

Randomly, we allocated C57BL/6 mice into four groups (n = 20 in each group). Afterwards, establishment of IPF model was accomplished via intratracheal administration of bleomycin (BLM, 5 mg/kg), while corresponding drug intervention was given accordingly. On 3rd, 7th, 14th and 28th days after modeling, we performed histopathological examination through staining. Meanwhile, immunohistochemistry (IHC) of PF and the expression of related factors were observed, while Ang/Tie2 pathway was assessed by ELISA with the effect of SSd on angiogenesis related proteins in IPF being explored with IHC and Western Blot technique.

RESULTS

Our results showed that SSd could reduce inflammation and PF levels in lung tissue of experimental mice, while levels of angiogenesis-related factors, namely Tie-2, Ang-1 and ANGPT2 (Ang-2), fibrosis- associated factors like Alpha-smooth muscle actin (α-SMA), collagen-I and hydroxyproline in SSd and dexamethasone (DXM) mice were significantly reduced at each time point compared to BLM (p < 0.01). Additionally, we discovered substantial decreased expressions of Ang-1, Ang-2, Tie-2, α-SMA and collagen-I at protein level in SSd and DXM mice at each time point compared to BLM (p < 0.05). Besides, insignificant differences were observed between SSd and DXM groups (p > 0.05).

CONCLUSION

This study has demonstrated that SSd could down-regulate the expression of ANG-1, Ang-2 and Tie2 in the Ang/Tie2 pathway, and may reduce lung inflammation and PF in BLM-induced mice via inhibition of angiogenesis.

AT2 receptor agonist LP2 restores respiratory function in a rat model of bleomycin-induced lung remodelling

This study aimed to evaluate the prophylactic and therapeutic potential of angiotensin II type 2 receptor peptide agonist LP2 in bleomycin-induced airway and cardiac remodeling in rats. Male Wistar rats were intratracheally instillated with bleomycin. Animals of a prophylactic arm received LP2 from day 0 at intraperitoneal doses of 1, 3 or 10 μg/kg/d, whereas animals from a therapeutic arm received this LP2 treatment from day 7. On day 28 direct lung mechanics were determined and cardiac and lung tissues were collected and (histo)morphologically assessed. Prophylactic LP2 at 1 µg/kg/d with bleomycin, versus bleomycin alone, significantly improved the airway pressure responses at fixed inflation of 4 ml (p < 0.05) and 7 ml volume (p < 0.05), static compliance (p < 0.01), inspiratory capacity (p < 0.05), lung tolerance of increased volume (p < 0.0001), right to left ventricular hypertrophy (p < 0.05). Therapeutic regime showed a similar trend as the prophylactic arm but was less effective, mostly lacking significance. However, and importantly, therapeutic LP2 at 1 µg/kg/d significantly decreased mRNA expression of collagen 1A1 (p < 0.01), of Connective Tissue Growth Factor 1 (p < 0.05) and of Tissue MetalloPeptidase inhibitor 1 (p < 0.05). In conclusion, a very low dose of 1 µg/kg/d LP2 has capacity to counter bleomycin-induced impairment of lung functioning and consequent cardiac remodeling.

Superiority of systemic bleomycin to intradermal HOCl for the study of interstitial lung disease

Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy, immune dysregulation, and multi-organ fibrosis. Interstitial lung disease (ILD) is a complication of SSc and a leading cause of SSc-death. The administration of hypochlorous acid (HOCl) intradermally in the mouse (HOCl-SSc) purportedly shows several features typical of SSc. We studied the model by injecting BALB/c mice daily intradermally with HOCl for 6-weeks, an exposure reported to induce lung fibrosis. On day 42, the skinfold thickness and the dermal thickness were two and three times larger respectively in the HOCl group compared to controls. HOCl treatment did not result in histological features of pulmonary fibrosis nor significant changes in lung compliance. Automated image analysis of HOCl mice lungs stained with picrosirius red did not show increased collagen deposition. HOCl injections did not increase pulmonary mRNA expression of pro-fibrotic genes nor induced the production of serum advanced oxidation protein products and anti-topoisomerase 1 antibodies. Immune cells in bronchoalveolar lavage fluid (BALF) and whole lung digests were not increased in HOCl-treated animals. Since lung fibrosis is proposed to be triggered by oxidative stress, we injected HOCl to Nrf2-/- mice, a mouse deficient in many antioxidant proteins. Lung compliance, histology, and BALF leukocyte numbers were comparable between Nrf2-/- mice and wild-type controls. We conclude that the HOCl-SSc model does not manifest SSc-lung disease.

Histone deacetylase 3 deletion in alveolar type 2 epithelial cells prevents bleomycin-induced pulmonary fibrosis

BACKGROUND

Epithelial mesenchymal transformation (EMT) in alveolar type 2 epithelial cells (AT2) is closely associated with pulmonary fibrosis (PF). Histone deacetylase 3 (HDAC3) is an important enzyme that regulates protein stability by modulating the acetylation level of non-histones. Here, we aimed to explore the potential role and regulatory mechanisms associated with HDAC3 in PF.

METHODS

We quantified HDAC3 expression both in lung tissues from patients with PF and from bleomycin (BLM)-treated mice. HDAC3 was also detected in TGF-β1-treated AT2. The mechanistic activity of HDAC3 in pulmonary fibrosis and EMT was also explored.

RESULTS

HDAC3 was highly expressed in lung tissues from patients with PF and bleomycin (BLM)-treated mice, especially in AT2. Lung tissues from AT2-specific HDAC3-deficient mice stimulated with BLM showed alleviative fibrosis and EMT. Upstream of HDAC3, TGF-β1/SMAD3 directly promoted HDAC3 transcription. Downstream of HDAC3, we also found that genetic or pharmacologic inhibition of HDAC3 inhibited GATA3 expression at the protein level rather than mRNA. Finally, we found that intraperitoneal administration of RGFP966, a selective inhibitor of HDAC3, could prevent mice from BLM-induced pulmonary fibrosis and EMT.

CONCLUSION

TGF-β1/SMAD3 directly promoted the transcription of HDAC3, which aggravated EMT in AT2 and pulmonary fibrosis in mice via deacetylation of GATA3 and inhibition of its degradation. Our results suggest that targeting HDAC3 in AT2 may provide a new therapeutic target for the prevention of PF.

A novel BRD4 degrader, ARV-825, attenuates lung fibrosis through senolysis and antifibrotic effect

BACKGROUND

Recent studies suggest that cellular senescence is related to the pathogenesis of idiopathic pulmonary fibrosis. However, cellular senescence has yet to be targeted therapeutically in clinical practice. ARV825, a recently developed BRD4 degrader, has been reported as a novel senolytic drug. Conversely, it has also been reported that BRD4 regulates the pro-fibrotic gene expression of fibroblasts. Therefore, this study focuses on the senolytic and anti-fibrotic effects of ARV825 and evaluated these effects on lung fibrosis.

METHODS

Lung fibroblasts were induced to senescence through serial passage. The expression of senescence markers and pro-fibrotic markers were determined through quantitative PCR or immunoblot analysis. Lung fibrosis was induced in mice through intratracheal administration of bleomycin. Mice treated with ARV825 underwent histological analysis of lung fibrosis using the Ashcroft score. Total lung collagen was quantified through a hydroxyproline assay. Respiratory mechanics analysis was performed using the flexiVent system.

RESULTS

For senescent cells, ARV825 induced the expression of an apoptosis marker while reducing the expression of BRD4 and senescence markers. On the other hand, for early passage pre-senescent cells, ARV825 reduced the expression of collagen type 1 and α-smooth muscle actin. In an experimental mouse model of lung fibrosis, ARV825 attenuated lung fibrosis and improved lung function. Immunohistochemical staining revealed a significant decrease in the number of senescent alveolar type 2 cells in lung tissue due to ARV825 treatment.

CONCLUSIONS

These results suggest that ARV825 may impact the progressive and irreversible course of fibrotic lung diseases.

Boningmycin induces AMPK-mediated endoplasmic reticulum-associated degradation of PD-L1 protein in human cancer cells

Anti-PD-1/PD-L1 monoclonal antibodies have displayed remarkable clinical benefits and revolutionized the treatment of multiple tumor types, but the low response rates and immune-related adverse events limit their application, which promoting the development of small molecule agents to improve the efficacy of PD-1/PD-L1 blockade therapy. Boningmycin (BON), a new small molecule belonging to bleomycin (BLM) family, exhibits potent anticancer activity in vitro and in vivo, as well as negligible lung toxicity, thereby can be an alternative of BLM. However, understandings about the anticancer mechanism of BLM-related compounds are extremely rare, it remains unclear if they affect PD-L1 level in a manner similar to that of other antitumor drugs. In this study, we discover that BON significantly reduces PD-L1 protein level in NCI-H460 and HT-1080 cells. Meanwhile, BON decreases the protein level of PD-L1 in a tumor xenograft model of NCI-H460 cells. Nevertheless, the mRNA level is not influenced after BON exposure. Furthermore, BON-induced PD-L1 reduction is proteasome- dependent. By using specific inhibitors and RNA interference technology, we confirm that the decline of PD-L1 protein by BON is mediated by AMPK-activated endoplasmic reticulum-associated degradation pathway, which is like to the action of metformin. Last but not the least, BON has synergism on gefitinib in vitro and in vivo. In conclusion, it is the first report demonstrating that BON decreases PD-L1 protein level through AMPK-mediated endoplasmic reticulum-associated degradation pathway. These findings will benefit the clinical transformation of BON and aid in the elucidation of molecular mechanism of BLM-related compounds.

FOXO4-D-Retro-Inverso targets extracellular matrix production in fibroblasts and ameliorates bleomycin-induced pulmonary fibrosis in mice

Pulmonary fibrosis (PF) occurs in various end stages of lung disease, and it is characterized by persistent scarring of the lung parenchyma with excessive deposition of extracellular matrix (ECM), leading to degressive quality of life and earlier mortality. FOXO4-D-Retro-Inverso (FOXO4-DRI), a synthesis peptide as a specific FOXO4 blocker, selectively induced dissociation of the FOXO4-p53 complex and nuclear exclusion of p53. Simultaneously, the p53 signaling pathway has been reported to activate in fibroblasts isolated from IPF fibrotic lung tissues and the p53 mutants cooperate with other factors that have the ability to disturb the synthesis of ECM. Yet, whether FOXO4-DRI influences the nuclear exclusion of p53 and then obstructs PF progress is still unknown. In this research, we explored the effect of FOXO4-DRI on bleomycin (BLM)-induced PF mouse model and activated fibroblasts model. The animal group of FOXO4-DRI therapeutic administration shows a milder pathologic change and less collagen deposition compared with the BLM-induced group. We also found the FOXO4-DRI resets the distribution of intranuclear p53 and concurrently decreased the total ECM proteins content. After further validation, FOXO4-DRI may well be a promising therapeutic approach to treating pulmonary fibrosis.

NMDA receptor activation induces damage of alveolar type II cells and lung fibrogenesis through ferroptosis

Ferroptosis, a newly discovered type of regulated cell death, has been implicated in numerous human diseases. Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal interstitial lung disease with poor prognosis and limited treatment options. Emerging evidence has linked ferroptosis and glutamate-determined cell fate which is considered a new light on the etiology of pulmonary fibrosis. Here, we observed that N-methyl d-aspartate receptor (NMDAR) activation promoted cell damage and iron deposition in MLE-12 cells in a dose-, time-, and receptor-dependent manner. This mediated substantial Ca2+ influx, upregulated the expression levels of nNOS and IRP1, and affected intracellular iron homeostasis by regulating the expression of iron transport-related proteins (i.e., TFR1, DMT1, and FPN). Excessive iron load promoted the continuous accumulation of total intracellular and mitochondrial reactive oxygen species, which ultimately led to ferroptosis. NMDAR inhibition reduced lung injury and pulmonary fibrosis in bleomycin-induced mice. Bleomycin stimulation upregulated the expression of NMDAR1, nNOS, and IRP1 in mouse lung tissues, which ultimately led to iron deposition via regulation of the expression of various iron metabolism-related genes. NMDAR activation initiated the pulmonary fibrosis process by inducing iron deposition in lung tissues and ferroptosis of alveolar type II cells. Our data suggest that NMDAR activation regulates the expression of iron metabolism-related genes by promoting calcium influx, increasing nNOS and IRP1 expression, and increasing iron deposition by affecting cellular iron homeostasis, ultimately leading to mitochondrial damage, mitochondrial dysfunction, and ferroptosis. NMDAR activation-induced ferroptosis of alveolar type II cells might be a key event to the initiation of pulmonary fibrosis.

Total sesquiterpenoids from Eupatorium lindleyanum DC. attenuate bleomycin-induced lung fibrosis by suppressing myofibroblast transition

Eupatorium lindleyanum DC. has been used as a functional food in China for a long time. However, the antifibrotic activity of total sesquiterpenoids from Eupatorium lindleyanum DC. (TS-EL) is still unknown. In this study, we discovered that TS-EL reduced the increase in α-smooth muscle actin (α-SMA), type I collagen and fibronectin content, the formation of cell filaments and collagen gel contraction in transforming growth factor-β1-stimulated human lung fibroblasts. Intriguingly, TS-EL did not change the phosphorylation of Smad2/3 and Erk1/2. TS-EL decreased the levels of serum response factor (SRF), a critical transcription factor of α-SMA, and SRF knockdown alleviated the transition of lung myofibroblasts. Furthermore, TS-EL significantly attenuated bleomycin (BLM)-induced lung pathology and collagen deposition and reduced the levels of two profibrotic markers, total lung hydroxyproline and α-SMA. TS-EL also decreased the levels of SRF protein expression in BLM-induced mice. These results suggested that TS-EL attenuates pulmonary fibrosis by inhibiting myofibroblast transition via the downregulation of SRF.

Pulmonary fibrosis and type-17 immunity

Fibrosis of the lung can occur in idiopathic pulmonary fibrosis, collagen vascular diseases, and hypersensitivity pneumonitis, among other diseases. Transforming growth factor (TGF)-β, vascular epithelial growth factor, fibroblast growth factor, and platelet-derived growth factor contribute to the pathophysiology of fibrosis. TGF-β and other cytokines, including interleukin (IL)-1β, IL-6, and IL-23, activate type-17 immunity, which is involved in pulmonary fibrosis. The components of type-17 immunity include type-17 helper T cells, γδT cells, IL-17A-producing CD8-positive T cells, invariant NKT cells, and group 3 innate lymphoid cells. IL-17A, the main cytokine of type-17 immunity, is able to induce the epithelial-mesenchymal transition in epithelial cells via a production of TGF-β, directly stimulate fibroblasts and fibrocytes, and inhibit autophagy, which otherwise protects against pulmonary fibrosis. IL-23 induces type-17 immunity and plays an important role in the acute exacerbation of pulmonary fibrosis. Clinical studies have also linked type-17 immunity to the pathogenesis of pulmonary fibrosis. Consequently, targeting type-17 immunity may serve as a new therapeutic strategy to prevent the development or exacerbation of pulmonary fibrosis.

[IL-33 up-regulates eIF3a expression by activating NF-κB signaling pathway to mediate the proliferation and differentiation of mouse pulmonary myofibroblasts and aggravate pulmonary fibrosis]

Objective To investigate the effects and mechanism of Interleukin-33 (IL-33) mediated proliferation and differentiation of pulmonary myofibroblasts (MFbs) in pulmonary fibrosis (PF). Methods C57BL/6 mice were randomly divided into four groups: a control group, a bleomycin (BLM) group, a BLM combined with IL-33 group and a BLM combined with anti-IL-33 antibody group, 12 mice in each group. The PF model was induced by intratracheal injection of BLM (5000 U/kg). The degrees of fibrosis were examined using HE and Masson staining. ELISA was used to measure the plasma levels of IL-33. Immunohistochemical staining was used to measure the expression of alpha smooth muscle actin (α-SMA) in lung tissue. Primary pulmonary fibroblasts were isolated and cultured from lung tissues of mice. The cells were divided into four groups: a control group, an IL-33 group, an IL-33 combined with dimethyl sulfoxide (DMSO) group and an IL-33 combined with pyrrolidine dithiocarbamate (PDTC) group. The cells were treated with DMSO or PDTC for 1 hour and then with IL-33 for 48 hours. Cell proliferation was measured by 5-ethynyl-2'-deoxyuridine (EdU) assay and cell cycle was measured by flow cytometry. TranswellTM assay was used to analyze cell migration. Real-time quantitative PCR was used to measure the expression of collagen type I (Col1), Col3 and α-SMA mRNA. The protein levels of IL-33, Col1, Col3, α-SMA, eukaryotic initiation factor 3a (eIF3a), phosphorylated IκBα (p-IκBα) (total lysate), p-NF-κB p65(total lysate) and NF-κB p65 (nucleus) were measured by Western blot analysis. Results In vivo, compared with the control group, the expressions of IL-33, p-IκBα (total lysate), p-NF-κB p65 (total lysate), NF-κB p65(nucleus), eIF3a, α-SMA, Col1 and Col3 in the BLM group significantly increased. Compared with the BLM group, the expressions of p-IκBα (total lysate), p-NF-κB p65 (total lysate), NF-κB p65 (nucleus), eIF3a, α-SMA, Col1 and Col3 in the IL-33 group increased further and the PF was further aggravated. But the effect of anti-IL-33 antibody was just opposite to that of IL-33. In vitro, IL-33 markedly induced the proliferation and migration of pulmonary fibroblasts, and significantly up-regulated the expression of p-IκBα (total lysate), p-NF-κB p65(total lysate), NF-κB p65 (nucleus), eIF3a, α-SMA, Col1 and Col3. But all these effects of IL-33 were reversed by pyrrolidine dithiocarbamate. Conclusion The results suggest that IL-33 may promote the expression of eIF3a by activating NF-κB signaling pathway, thus inducing the proliferation and differentiation of MFbs and promoting the occurrence and development of PF.

Loss of IGFBP2 mediates alveolar type 2 cell senescence and promotes lung fibrosis

Accumulation of senescent cells contributes to age-related diseases including idiopathic pulmonary fibrosis (IPF). Insulin-like growth factor binding proteins (IGFBPs) regulate many biological processes; however, the functional contributions of IGFBP2 in lung fibrosis remain largely unclear. Here, we report that intranasal delivery of recombinant IGFBP2 protects aged mice from weight loss and demonstrated antifibrotic effects after bleomycin lung injury. Notably, aged human-Igfbp2 transgenic mice reveal reduced senescence and senescent-associated secretory phenotype factors in alveolar epithelial type 2 (AEC2) cells and they ameliorated bleomycin-induced lung fibrosis. Finally, we demonstrate that IGFBP2 expression is significantly suppressed in AEC2 cells isolated from fibrotic lung regions of patients with IPF and/or pulmonary hypertension compared with patients with hypersensitivity pneumonitis and/or chronic obstructive pulmonary disease. Altogether, our study provides insights into how IGFBP2 regulates AEC2-cell-specific senescence and that restoring IGFBP2 levels in fibrotic lungs can prove effective for patients with IPF.

Aspirin alleviates pulmonary fibrosis through PI3K/AKT/mTOR-mediated autophagy pathway

Idiopathic pulmonary fibrosis (IPF) is a chronic and irreversible lung disease with limited therapeutic options. Aspirin can alleviate liver, kidney, and cardiac fibrosis. However, its role in lung fibrosis is unclear. This study aims to investigate the effects of aspirin on lung fibroblast differentiation and pulmonary fibrosis. TGF-β1-induced human embryonic lung fibroblasts, IPF lung fibroblasts, and bleomycin-induced lung fibrosis mouse model were used in this study. The results showed that aspirin significantly decreased the expression of Collagen 1A1, Fibronectin, Alpha-smooth muscle actin, and equestosome1, and increased the ratio of light chain 3 beta II/I and the number of autophagosome in vivo and in vitro; reduced bleomycin-induced lung fibrosis. Aspirin also decreased the ratios of phosphorylated phosphatidylinositol 3 kinase (p-PI3K)/PI3K, protein kinase B (p-AKT)/AKT, and mechanistic target of rapamycin (p-mTOR)/mTOR in vitro. Autophagy inhibitor 3-methyladenine, bafilomycin-A1, and AKT activator SC-79 abrogated the effects of aspirin. These findings indicate that aspirin ameliorates pulmonary fibrosis through a PI3K/AKT/mTOR-dependent autophagy pathway.

Astragaloside IV alleviates senescence of vascular smooth muscle cells through activating Parkin-mediated mitophagy

Astragaloside IV (AS-IV), as one of the main active components of Astragalus membranaceus, has been reported to have cardiovascular protective effects. However, the role and molecular mechanism of AS-IV in vascular senescence have not been clearly stated. The in vitro aging model was constructed using bleomycin (BLM) in vascular smooth muscle cells (VSMCs). Cell senescence were assessed through Western blotting analysis of aging markers, flow cytometry, and the β-galactosidase (SA-β-Gal) kit. Mitophagy was determined through transmission electron microscopy, TMRM staining, and Western blotting analysis of p62. A model of aging blood vessels was induced by D-gal. The vascular wall thickness of mice was also evaluated by H&E staining. Our data proved that AS-IV plays an anti-senescent role in vitro and in vivo. Results showed that AS-IV effectively improved mitochondrial injury, raised MMP, and mediated mitophagy in BLM-induced senescent VSMCs and D-gal induced aging mice. Parkin expression strengthened AS-IV's anti-senescent function. In conclusions, AS-IV attenuated BLM-induced VSMC senescence via Parkin to regulate mitophagy. Therefore, AS-IV-mediated Parkin might be a latent therapeutic agent and target for VSMC senescence.

Perfluorocarbon Nanoemulsions Enhance Therapeutic siRNA Delivery in the Treatment of Pulmonary Fibrosis

Local pulmonary administration of therapeutic siRNA represents a promising approach to the treatment of lung fibrosis, which is currently hampered by inefficient delivery. Development of perfluorooctylbromide (PFOB) nanoemulsions as a way of improving the efficiency of pulmonary polycation-based delivery of siRNA is reported. The results show that the polycation/siRNA/PFOB nanoemulsions are capable of efficiently silencing the expression of STAT3 and inhibiting chemokine receptor CXCR4-two validated targets in pulmonary fibrosis. Both in vitro and in vivo results demonstrate that the nanoemulsions improve mucus penetration and facilitate effective cellular delivery of siRNA. Pulmonary treatment of mice with bleomycin-induced pulmonary fibrosis shows strong inhibition of the progression of the disease and significant prolongation of animal survival. Overall, the study points to a promising local treatment strategy of pulmonary fibrosis.

Efficacy of Qingfei oral liquid for idiopathic pulmonary fibrosis in rats and related network pharmacology study

To investigate the therapeutic effect and mechanism of Qingfei oral liquid in idiopathic pulmonary fibrosis. Seventy-two male SD rats were divided into control group, model group, pirofenidone group and Qingfei group with 18 animals in each group. The idiopathic pulmonary fibrosis was induced in last three groups by intratracheal injection of bleomycin; pirofenidone group was given oral administration of pirofenidone b.i.d for 21 d, and Qingfei group was given Qingfei oral liquid 3.6 mL/kg q.d for Lung tissues were obtained for HE staining, Masson staining and transforming growth factor (TGF)-β immunohistochemical staining. Superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) were detected in tissue homogenates. The BATMAN-TCM database was used to retrieve the chemical components and their corresponding targets of Qingfei oral solution by network pharmacology method, and then the component-target-disease network diagram was constructed. Finally, the pathway enrichment analysis was carried out to explore the molecular mechanism of Qingfei oral liquid against idiopathic fibrosis. Histopathology results showed that Qingfei oral liquid had a similar relieving effect on pulmonary fibrosis as the positive drug pirfenidone; TGF-β secretion had a significant reduction in lung tissues of Qingfei group; and Qingfei oral liquid had better regulatory effect on SOD, MDA and GSH than pirfenidone. The results of component-target-disease network and pathway enrichment analysis showed that the related molecular pathways were concentrated in inflammation, extracellular matrix and cytokines. Qingfei oral liquid has a good therapeutic effect on idiopathic pulmonary fibrosis in rats via regulation of inflammation, extracellular matrix and cytokines.

Expression of the α7 Nicotinic Acetylcholine Receptor Is Critically Required for the Antifibrotic Effect of PHA-543613 on Skin Fibrosis

INTRODUCTION

Targeting the α7 nicotinic acetylcholine receptor (α7nAChR) has recently been suggested as a potential new treatment for fibrotic skin diseases. Here, we performed a genetic and pharmacologic approach to clarify the role of this receptor in the bleomycin (BLM) mouse model of skin fibrosis using α7nAChR KO mice.

METHODS

We analyzed the expression of extracellular matrix (ECM) components in murine skin using quantitative RT-PCR, pepsin digestion/SDS-PAGE of proteins and performed hydroxyproline assays as well as histological/immunohistochemical staining of skin sections. To identity the target cells of the α7nAChR agonist PHA-543613, we used murine dermal fibroblasts (MDF). We tested their response to the profibrotic cytokine transforming growth factor-β1 (TGF-β1) and utilized gene silencing to elucidate the role of the α7nAChR.

RESULTS

We confirmed our previous findings on C3H/HeJ mice and detected a suppressive effect of PHA-543613 on BLM-induced skin fibrosis in the mouse strain C57BL/6J. This antifibrotic effect of PHA-543613 was abrogated in α7nAChR-KO mice. Interestingly, α7nAChR-KO animals exhibited a basal profibrotic signature by higher RNA expression of ECM genes and hydroxyproline content than WT mice. In WT MDF, PHA-543613 suppressed ECM gene expression induced by TGF-β1. Gene silencing of α7nAChR by small interfering RNA neutralized the effects of PHA-543613 on TGF-β1-mediated ECM gene expression.

CONCLUSION

In summary, we have identified the α7nAChR as the essential mediator of the antifibrotic effect of PHA-543613. MDF are directly targeted by PHA-543613 to suppress collagen synthesis. Our findings emphasize therapeutic exploitation of α7nAChR receptor agonists in fibrotic skin diseases.

Remarkable enhancement of bleomycin production through precise amplification of its biosynthetic gene cluster in Streptomyces verticillus

Amplification of biosynthetic gene clusters is important to increase secondary metabolite production. However, the copy number of amplified gene clusters is difficult to control precisely. In this study, the tandem amplification of a 70 kb bleomycin biosynthetic gene cluster was precisely regulated through the combined strategy of a ZouA-dependent DNA amplification system and double-reporter-guided recombinant selection in Streptomyces verticillus ATCC15003. The production of bleomycin in the recombinant strain containing six copies of the bleomycin gene cluster was 9.59-fold higher than that in the wild-type strain. The combined strategy used in this study is powerful and applicable for precisely regulating the amplification of gene clusters and improving the corresponding secondary metabolite production.

Metabolomic study on bleomycin and polyhexamethylene guanidine phosphate-induced pulmonary fibrosis mice models

INTRODUCTION

Polyhexamethylene guanidine phosphate (PHMG) has been used as a disinfectant and biocide, and was known to be harmless and non-toxic. However, in 2011, PHMG used as a humidifier disinfectant was reported to be associated with lung diseases, such as, fibrosis in the toxicant studies on pulmonary fibrosis by PHMG. However, no metabolomics study has been performed in PHMG-induced mouse models of pulmonary fibrosis.

OBJECTIVES

We performed a metabolomic study to understand the biochemical events that occur in bleomycin (BLM)- and PHMG-induced mouse models of pulmonary fibrosis using gas chromatography-mass spectrometry (GC-MS), LC-tandem MS, and GC-tandem MS.

RESULTS

The levels of 61 metabolites of 30 amino acids, 13 organic acids, 12 fatty acids, 5 polyamines, and oxidized glutathione were determined in the pulmonary tissues of mice with BLM- and PHMG-induced pulmonary fibrosis and in normal controls. Principal component analysis and partial least squares discriminant analysis used to compare level of these 61 metabolites in pulmonary tissues. Levels of metabolites were significantly different in the BLM and PHMG groups as compared with the control group. In particular, the BLM- and PHMG-induced pulmonary fibrosis models showed elevated collagen synthesis and oxidative stress and metabolic disturbance of TCA related organic acids including fumaric acid by NADPH oxidase. In addition, polyamine metabolism showed severe alteration in the PHMG group than that of the BLM group.

CONCLUSION

This result suggests PHMG will be able to induce pulmonary fibrosis by arginine metabolism and NADPH oxidase signaling.

Lineage context switches the function of a C. elegans Pax6 homolog in determining a neuronal fate

The sensory nervous system of C. elegans comprises cells with varied molecular and functional characteristics, and is, therefore, a powerful model for understanding mechanisms that generate neuronal diversity. We report here that VAB-3, a C. elegans homolog of the homeodomain-containing protein Pax6, has opposing functions in regulating expression of a specific chemosensory fate. A homeodomain-only short isoform of VAB-3 is expressed in BAG chemosensory neurons, where it promotes gene expression and cell function. In other cells, a long isoform of VAB-3, comprising a Paired homology domain and a homeodomain, represses expression of ETS-5, a transcription factor required for expression of BAG fate. Repression of ets-5 requires the Eyes Absent homolog EYA-1 and the Six-class homeodomain protein CEH-32. We determined sequences that mediate high-affinity binding of ETS-5, VAB-3 and CEH-32. The ets-5 locus is enriched for ETS-5-binding sites but lacks sequences that bind VAB-3 and CEH-32, suggesting that these factors do not directly repress ets-5 expression. We propose that a promoter-selection system together with lineage-specific expression of accessory factors allows VAB-3/Pax6 to either promote or repress expression of specific cell fates in a context-dependent manner. This article has an associated 'The people behind the papers' interview.

Bleomycin Can Cleave an Oncogenic Noncoding RNA

Noncoding RNAs are pervasive in cells and contribute to diseases such as cancer. A question in biomedical research is whether noncoding RNAs are targets of medicines. Bleomycin is a natural product that cleaves DNA; however, it is known to cleave RNA in vitro. Herein, an in-depth analysis of the RNA cleavage preferences of bleomycin A5 is presented. Bleomycin A5 prefers to cleave RNAs with stretches of AU base pairs. Based on these preferences and bioinformatic analysis, the microRNA-10b hairpin precursor was identified as a potential substrate for bleomycin A5. Both in vitro and cellular experiments demonstrated cleavage. Importantly, chemical cleavage by bleomycin A5 in the microRNA-10b hairpin precursors occurred near the Drosha and Dicer enzymatic processing sites and led to destruction of the microRNA. Evidently, oncogenic noncoding RNAs can be considered targets of cancer medicines and might elicit their pharmacological effects by targeting noncoding RNA.

Horizontal gene transfer drives adaptive colonization of apple trees by the fungal pathogen Valsa mali

Horizontal gene transfer (HGT) often has strong benefits for fungi. In a study of samples from apple canker in Shaanxi Province, China, diverse microbes, along with the necrotrophic pathogen Valsa mali, were found to colonize the apple bark, thus providing ample opportunity for HGT to occur. In the present study, we identified 32 HGT events in V. mali by combining phyletic distribution-based methods with phylogenetic analyses. Most of these HGTs were from bacteria, whereas several others were from eukaryotes. Three HGTs putatively functioned in competition with actinomycetes, some of which showed a significant inhibitory effect on V. mali. Three HGTs that were probably involved in nitrogen uptake were also identified. Ten HGTs were thought to be involved in pathogenicity because they were related to known virulence factors, including cell wall-degrading enzymes and candidate effector proteins. HGT14, together with HGT32, was shown to contribute to bleomycin resistance of V. mali.These results suggest that HGT drives the adaptive evolution of V. mali. The HGTs identified here provide new clues for unveiling the adaptation mechanisms and virulence determinants of V. mali.

Recent advances in antitumor antibiotics

An effective treatment schedule with bleomycin in combination with mitomycin and a new effective area in treatment with neocarzinostatin was introduced. Studies on more useful derivatives or analogues of bleomycin and anthracycline antitumor antibiotics were described. Bleomycin PEP thus selected may become a useful agent. Aclacinomycin and various other anthracycline glycosides were isolated from beer fermentation and tested. Future progress in microbiol secondary metabolites useful in cancer treatment was discussed.

Interactions of antineoplastic antibiotics and DNA

Basic concepts of interaction of antineoplastic antibiotics with DNA are discussed and information concerning the effects of actinomycins, olivomycin and related antibiotics, anthracyclines, sibiromycin, mitomycin C, bruneomycin, and bleomycin is summarized.

MicroRNA-21 in scleroderma fibrosis and its function in TGF-β-regulated fibrosis-related genes expression

Uncontrolled fibrosis in multiple organs is the main cause of death in systemic sclerosis (SSc), and transforming growth factor-β (TGF-β) activation plays a fundamental role in the process. Our previous study demonstrated that miR-21 was significantly up-regulated in SSc fibroblasts. Here, we found that TGF-β regulated the expression of miR-21 and fibrosis-related genes, and decreased Smad7 expression. Over-expression of miR-21 in fibroblasts decreased the levels of Smad7, whereas knockdown of miR-21 increased its expression. Further study using a reporter gene assay demonstrated Smad7 was a direct target of miR-21. Similar to human SSc, the expression of miR-21 increased in the bleomycin induced skin fibrosis. Inhibition of fibrosis by treatment with anti-fibrosis drug bortezomib restored the levels of miR-21 and Smad7. MiR-21 may function in an amplifying circuit to enhance TGF-β signaling events in SSc fibrosis, and suggesting that miR-21 may act as a potential therapeutic target.

Differential cellular effects of electroporation and electrochemotherapy in monolayers of human microvascular endothelial cells

In vivo electroporation of tumours shows disruption of blood flow and creates a vascular effect with an initial rapid and transient vasoconstriction phase and a much longer lasting phase with changed microvascular endothelium. These changes are not well understood but are presumed to involve the cytoskeleton. The paper presents for the first time differential in vitro effects describing cytoskeleton changes and monolayer integrity changes by both electroporation and electrochemotherapy of monolayers of human microvascular endothelial cells (HMEC-1). After the application of electric field pulses, the morphology of cells, and both the F-actin and Beta-tubulin cytoskeleton proteins were affected. During both electroporation and electrochemotherapy, the initial phase of cellular damage was noticed at 10 min as swollen cells and honeycomb-like actin bundles. The electroporation-induced cellular effects, observed from electric pulses >150 V, were voltage-dependent and within 24 hrs partly recoverable. The electrochemotherapy-induced cellular effects developed at 2 hrs in spindle-like cells, and more densely packed F-actin and Beta-tubulin were observed, which were dependent on the amount of bleomycin and the voltages applied (>50 V). In addition, for electrochemotherapy with electric pulses >150 V cellular changes were not recoverable within 24 hrs. The effects on monolayer integrity were reflected in the enhanced monolayer permeability, with the electrochemotherapy showing an earlier onset and synergy. We conclude that electrochemotherapy as compared to electroporation leads within 24 hrs to a quicker and more pronounced monolayer integrity damage and endothelial cell death, which together provide further insight into the cellular changes of the vascular disruption of electrochemotherapy.

Comparative analysis of the biosynthetic gene clusters and pathways for three structurally related antitumor antibiotics: bleomycin, tallysomycin, and zorbamycin

The biosynthetic gene clusters for the glycopeptide antitumor antibiotics bleomycin (BLM), tallysomycin (TLM), and zorbamycin (ZBM) have been recently cloned and characterized from Streptomyces verticillus ATCC15003, Streptoalloteichus hindustanus E465-94 ATCC31158, and Streptomyces flavoviridis ATCC21892, respectively. The striking similarities and differences among the biosynthetic gene clusters for the three structurally related glycopeptide antitumor antibiotics prompted us to compare and contrast their respective biosynthetic pathways and to investigate various enzymatic elements. The presence of different numbers of isolated nonribosomal peptide synthetase (NRPS) domains in all three clusters does not result in major structural differences of the respective compounds. The seemingly identical domain organization of the NRPS modules responsible for heterocycle formation, on the other hand, is contrasted by the biosynthesis of two different structural entities, bithiazole and thiazolinyl-thiazole, for BLM/TLM and ZBM, respectively. Variations in sugar biosynthesis apparently dictate the glycosylation patterns distinct for each of the BLM, TLM, and ZBM glycopeptide scaffolds. These observations demonstrate nature's ingenuity and flexibility in achieving structural differences and similarities via various mechanisms and will surely inspire combinatorial biosynthesis efforts to expand on natural product structural diversity.

Biochemical evaluation of a 108-member deglycobleomycin library: viability of a selection strategy for identifying bleomycin analogues with altered properties

The bleomycins (BLMs) are clinically used glycopeptide antitumor antibiotics that have been shown to mediate the sequence-selective oxidative damage of both DNA and RNA. Previously, we described the solid-phase synthesis of a library of 108 unique analogues of deglycoBLM A6, a congener that cleaves DNA analogously to BLM itself. Each member of the library was assayed for its ability to effect single- and double-strand nicking of duplex DNA, sequence-selective DNA cleavage, and RNA cleavage in the presence and absence of a metal ion cofactor. All of the analogues tested were found to mediate concentration-dependent plasmid DNA relaxation to some extent, and a number exhibited double-strand cleavage with an efficiency comparable to or greater than deglycoBLM A6. Further, some analogues having altered linker and metal-binding domains mediated altered sequence-selective cleavage, and a few were found to cleave a tRNA3Lys transcript both in the presence and in the absence of a metal cofactor. The results provide insights into structural elements within BLM that control DNA and RNA cleavage. The present study also permits inferences to be drawn regarding the practicality of a selection strategy for the solid-phase construction and evaluation of large libraries of BLM analogues having altered properties.

Methionine aminopeptidase-2 as a selective target of myofibroblasts in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, scarring lung disease characterized by fibroblast accumulation and deposition of collagen. Factors that promote growth and/or survival of fibroblasts are potential therapeutic targets. Methionine aminopeptidase 2 (MetAP2), a member of the aminopeptidase family of proteases, has been implicated in cell proliferation in a variety of cell types, but its expression and function in the lung is not known. By immunohistochemistry, MetAP2 was expressed in many cell types, including fibroblasts, in IPF lungs. Fumagillin, an irreversible inhibitor of the enzymatic activity of MetAP2, attenuated collagen deposition in the bleomycin model of acute lung injury in mice. Treatment with fumagillin caused a selective reduction in the numbers of bromodeoxyuridine (BrdU)-positive myofibroblasts, but not type II alveolar epithelial cells, macrophages, or B- and T-lymphocytes in the lungs of bleomycin-treated mice. Incubation of primary rat lung fibroblasts with either fumagillin or with short interfering RNA that targeted MetAP2 led to reduced proliferation, as assessed by incorporation of BrdU. The profibrotic growth factor, platelet-derived growth factor, increased expression of MetAP2 in rat lung fibroblasts. We propose that MetAP2 plays a role in the proliferation of fibroblasts and myofibroblasts in fibrotic lung diseases and may serve as a novel pharmacologic target in IPF.

trans Autophosphorylation at DNA-dependent protein kinase's two major autophosphorylation site clusters facilitates end processing but not end joining

Recent studies have established that DNA-dependent protein kinase (DNA-PK) undergoes a series of autophosphorylation events that facilitate successful completion of nonhomologous DNA end joining. Autophosphorylation at sites in two distinct clusters regulates DNA end access to DNA end-processing factors and to other DNA repair pathways. Autophosphorylation within the kinase's activation loop regulates kinase activity. Additional autophosphorylation events (as yet undefined) occur that mediate kinase dissociation. Here we provide the first evidence that autophosphorylation within the two major clusters (regulating end access) occurs in trans. Further, both UV-induced and double-strand break (DSB)-induced phosphorylation in the two major clusters is predominantly autophosphorylation. Finally, we show that while autophosphorylation in trans on one of two synapsed DNA-PK complexes facilitates appropriate end processing, this is not sufficient to promote efficient end joining. This suggests that end joining in living cells requires additional phosphorylation events that either occur in cis or that occur on both sides of the DNA-PK synapse. These data support an emerging consensus that, via a series of autophosphorylation events, DNA-PK undergoes a sequence of conformational changes that promote efficient and appropriate repair of DSBs.

[Relationship between the expression of P-glycoprotein, glutathione S-transferase-pi and thymidylate synthase proteins and adenosine triphosphate tumor chemosensitivity assay in cervical cancer]

OBJECTIVE

To explore the feasibility of the adenosine triphosphate-tumor chemosensitivity assay (ATP-TCA) in human cervical cancer chemosensitivity testing and to analyze the relationship between the three drug resistance-associated proteins: P-glycoprotein (P-gp); glutathione S-transferase-pi (GST-pi); thymidylate synthase (TS) and ATP-TCA.

METHODS

ATP-TCA was used to detect the sensitivity of 35 specimens of fresh cervical cancer to six cytotoxic drugs as follows: paclitaxel (TAX), cisplatin (DDP), bleomycin (BLM), gemcitabine (GEM), 5-fluorouracil (5-FU), irinotecan (CPT-11). Consecutive sections from 35 cases of cervical cancer were assessed immunohistochemically for expression of P-gp, GST-pi and TS proteins.

RESULTS

(1) Thirty-two of 35 assays were completed successfully, with an evaluability rate of ATP-TCA at 91% (32/35). There was a marked heterogeneity of chemosensitivity in cervical cancer. The ex vivo sensitive rate of TAX was 88% (28/32), of 5-FU 72% (23/32), of GEM 62% (20/32), of DDP 19% (6/32), of BLM 16% (5/32), and of CPT-11 12% (4/32). (2) The expression of GST-pi and TS protein in cervical cancer was 66% (21/32) and 44% (14/32), which was associated with the resistance to DDP and 5-FU ex vivo (P=0.011, P=0.022), respectively; but the expression of P-gp protein was not associated with any resistance to TAX, 5-FU, GEM, DDP, BLM or CPT-11 ex vivo (P>0.05).

CONCLUSIONS

ATP-TCA could be used to individualize chemotherapy by selecting agents for particular patients of cervical cancer. The expression of GST-pi and TS protein might be useful biomarkers to predict the resistance to DDP and 5-FU in patients with cervical cancer.

The mitomycin C (MMC)-binding protein from MMC-producing microorganisms protects from the lethal effect of bleomycin: crystallographic analysis to elucidate the binding mode of the antibiotic to the protein

Antibiotic-producing microorganisms must be protected from the lethal effect of their own antibiotic. We have previously determined the X-ray crystal structure of the bleomycin (Bm)-binding protein, designated BLMA, as a self-resistance determinant from Bm-producing Streptomyces verticillus, which suggests that the binding of the first Bm to one of two pockets formed in the BLMA homodimer induces the cooperative binding of the second Bm to the other pocket. In the present study, we noticed that the X-ray crystallographic structure of a self-resistance determinant from a mitomycin C-producing microorganism, designated MRDP, reveals similarity to the folding pattern on the BLMA, although no sequence homology exists. To clarify the hypothesis that MRDP may function as a resistance determinant to Bm, we characterized and determined the crystal structure of MRDP complexed with the Cu(II)-bound form of BmA(2) grouped into the Bm family of antibiotics. The biochemical and structural studies for Bm binding provide evidence that the first Bm binds anti-cooperatively to a pocket of MRDP with binding affinity of the nanomolar order, whereas the second Bm binds to the other pocket, which has binding affinity of the micromolar order. The invisibility of the second Bm in the structure agrees with the observation that Escherichia coli-expressing MRDP displays lower resistance to Bm than that expressing BLMA. The structure of MRDP, which is complexed with the Cu(II)-bound BmA(2), revealed that the gamma-aminopropyldimethylsulphonium moiety of the antibiotic is sandwiched between the peripheral residues of the binding pocket and that its positively charged sulphonium head is accommodated completely in the negatively charged region of the MRDP pocket. Furthermore, the Cu(II)-bound BmA(2) has a very compact structure, in which the bithiazole ring of BmA(2) is folded back to the metal-binding domain.

Ligation of protease-activated receptor 1 enhances alpha(v)beta6 integrin-dependent TGF-beta activation and promotes acute lung injury

Activation of latent TGF-beta by the alpha(v)beta6 integrin is a critical step in the development of acute lung injury. However, the mechanism by which alpha(v)beta6-mediated TGF-beta activation is regulated has not been identified. We show that thrombin, and other agonists of protease-activated receptor 1 (PAR1), activate TGF-beta in an alpha(v)beta6 integrin-specific manner. This effect is PAR1 specific and is mediated by RhoA and Rho kinase. Intratracheal instillation of the PAR1-specific peptide TFLLRN increases lung edema during high-tidal-volume ventilation, and this effect is completely inhibited by a blocking antibody against the alpha(v)beta6 integrin. Instillation of TFLLRN during high-tidal-volume ventilation is associated with increased pulmonary TGF-beta activation; however, this is not observed in Itgb6-/- mice. Furthermore, Itgb6-/- mice are also protected from ventilator-induced lung edema. We also demonstrate that pulmonary edema and TGF-beta activity are similarly reduced in Par1-/- mice following bleomycin-induced lung injury. These results suggest that PAR1-mediated enhancement of alpha(v)beta6-dependent TGF-beta activation could be one mechanism by which activation of the coagulation cascade contributes to the development of acute lung injury, and they identify PAR1 and the alpha(v)beta6 integrin as potential therapeutic targets in this condition.

Evidence for TGF-ß1 and bleomycin intracellular signaling through autocrine regulation of Smad 3 binding to the proximal promoter of theSmad 7 gene

Both Bleomycin and TGF-beta1 increase the transcription of the COL1A1 gene. Bleomycin acts through TGF-beta1. Bleomycin stimulates the COL1A1 promoter through the distal TGF-beta response element by intracellular and extracellular signaling. As demonstrated in this manuscript, Bleomycin's intracellular signaling can be explained by a decrease of Smad 3 transcription factor binding to the SBE located in the proximal promoter of the inhibitory Smad 7 gene. This would result in TGF-beta1-induced activated SMADS, which would result in more collagen. Bleomycin's extracellular signaling results from the secretion of more latent TGF-beta produced by lung fibroblasts and cleaved to active TGF-beta extracellularly. Since the TGF-beta genes are auto-induced in human embryonic IMR-90 lung fibroblasts, this study indicates an autocrine mechanism to maintain homeostasis in vivo for fibroblasts and other cell types, which produce TGF-beta1 to limit the fibrogenic response to TGF-beta1 and Bleomycin.

Application of microdialysis to study thein vivo release of pingyangmycin fromin situ gels in rabbits

Microdialysis was used together with HPLC to monitor the local concentration of pingyangmycin hydrochloride (PYM) after embolizing rabbit ear-veins with an injectable sustained release formulation, PYM-Zein/PYM-Zein-sucrose acetate isobutyrate (SAIB), in situ gel. The dialysis probe was perfused at 2 microL/min. The in vivo recovery was 46.6 3.1% (n = 4). The samples were injected directly into HPLC. PYM was detected using UV detector at 291 nm. Separation from other components in the dialysate was performed using a Discovery((R)) RP-Amide C(16) column within 12 min. The response for PYM in the dialysate was linear (r(2) > 0.996) over the range of 2.5-212 microg/mL. The limit of detection and limit of quantitation of PYM in the dialysate were 0.4 and 1.5 microg/mL, respectively. The results demonstrated that the in situ gel of PYM-Zein-SAIB could extend the release of PYM to 4 days. SAIB could significantly cut down the initial burst of PYM from the in situ gels (p < 0.05).

Novel peptide derivatives of bleomycin A5: Synthesis, antitumor activity and interaction with DNA

A series of novel amino acid and peptide derivatives of bleomycin (BLM) A(5) were synthesized. All the compounds possessed significant antitumor activities in vitro against HL-60, BGC-823, PC-3MIE8, and MDA-MB-435 cell lines. Their antitumor activities against MDA-MB-435 were 10-fold higher than BLM A5. The DNA cleavage studies indicated that the hydrophobic amino acid or peptide derivatives of BLM A5 could induce higher cleavage ratio of double to single strand DNA than BLM A5. From the DNA binding studies, we found that the derivatives containing either D-conformation amino acid or basic amino acid could facilitate DNA binding of BLM.