Tacrolimus alleviates pulmonary fibrosis progression through inhibiting the activation and interaction of ILC2 and monocytes.

Idiopathic pulmonary fibrosis (IPF) is a heterogeneous group of lung diseases with different etiologies and characterized by progressive fibrosis. This disease usually causes pulmonary structural remodeling and decreased pulmonary function. The median survival of IPF patients is 2-5 years. Predominantly accumulation of type II innate immune cells accelerates fibrosis progression by secreting multiple pro-fibrotic cytokines. Group 2 innate lymphoid cells (ILC2) and monocytes/macrophages play key roles in innate immunity and aggravate the formation of pro-fibrotic environment. As a potent immunosuppressant, tacrolimus has shown efficacy in alleviating the progression of pulmonary fibrosis. In this study, we found that tacrolimus is capable of suppressing ILC2 activation, monocyte differentiation and the interaction of these two cells. This effect further reduced activation of monocyte-derived macrophages (Mo-M), thus resulting in a decline of myofibroblast activation and collagen deposition. The combination of tacrolimus and nintedanib was more effective than either drug alone. This study will reveal the specific process of tacrolimus alleviating pulmonary fibrosis by regulating type II immunity, and explore the potential feasibility of tacrolimus combined with nintedanib in the treatment of pulmonary fibrosis. This project will provide new ideas for clinical optimization of anti-pulmonary fibrosis drug strategies.

IL20Rb aggravates pulmonary fibrosis through enhancing bone marrow derived profibrotic macrophage activation.

Idiopathic pulmonary fibrosis (IPF) is one of the most fatal chronic interstitial lung diseases with unknown pathogenesis, current treatments cannot truly reverse the progression of the disease. Pulmonary macrophages, especially bone marrow derived pro-fibrotic macrophages, secrete multiple kinds of profibrotic mediators (SPP1, CD206, CD163, IL-10, CCL18…), thus further promote myofibroblast activation and fibrosis procession. IL20Rb is a cell-surface receptor that belongs to IL-20 family. The role of IL20Rb in macrophage activation and pulmonary fibrosis remains unclear. In this study, we established a bleomycin-induced pulmonary fibrosis model, used IL4/13-inducing THP1 cells to induce profibrotic macrophage (M2-like phenotype) polarization models. We found that IL20Rb is upregulated in the progression of pulmonary fibrosis, and its absence can alleviate the progression of pulmonary fibrosis. In addition, we demonstrated that IL20Rb promote the activation of bone marrow derived profibrotic macrophages by regulating the Jak2/Stat3 and Pi3k/Akt signaling pathways. In terms of therapeutic strategy, we used IL20Rb neutralizing antibodies for animal administration, which was found to alleviate the progression of IPF. Our results suggest that IL20Rb plays a profibrotic role by promoting profibrotic macrophage polarization, and IL20Rb may become a potential therapeutic target for IPF. Neutralizing antibodies against IL20Rb may become a potential drug for the clinical treatment of IPF.

Favipiravir ameliorates bleomycin-induced pulmonary fibrosis by reprogramming M1/M2 macrophage polarization.

Corona Virus Disease 2019 (COVID-19) is an infectious disease that seriously endangers human life and health. The pathological anatomy results of patients who died of the COVID-19 showed that there was an excessive inflammatory response in the lungs. It is also known that most of the COVID-19 infected patients will cause different degrees of lung damage after infection, and may have pulmonary fibrosis remaining after cure. Macrophages are a type of immune cell population with pluripotency and plasticity. In the early and late stages of infection, the dynamic changes of the balance and function of M1/M2 alveolar macrophages have a significant impact on the inflammatory response of the lungs. In the early stage of pulmonary fibrosis inflammation, the increase in the proportion of M1 type is beneficial to clear pathogenic microorganisms and promote the progress of inflammation; in the later stage of fibrosis, the increase in the number of M2 type macrophages can inhibit the inflammatory response and promote the degradation of fibrosis. As a potential treatment drug for new coronavirus pneumonia, favipiravir is in the process of continuously carried out relevant clinical trials. This study aims to discuss whether the antiviral drug favipiravir can suppress inflammation and immune response by regulating the M1/M2 type of macrophages, thereby alleviating fibrosis. We established a bleomycin-induced pulmonary fibrosis model, using IL-4/13 and LPS/IFN-γ cell stimulating factor to induce macrophage M1 and M2 polarization models, respectively. Our study shows that favipiravir exerts anti-fibrotic effects mainly by reprogramming M1/M2 macrophages polarization, that is, enhancing the expression of anti-fibrotic M1 type, reducing the expression of M2 type pro-fibrotic factors and reprogramming it to anti-fibrotic phenotype. Aspects of pharmacological mechanisms, favipiravir inhibits the activation of JAK2-STAT6 and JAK2-PI3K-AKT signaling by targeting JAK2 protein, thereby inhibiting pro-fibrotic M2 macrophages polarization and M2-induced myofibroblast activation. In summary, favipiravir can reduce the progression of pulmonary fibrosis, we hope to provide a certain reference for the treatment of pulmonary fibrosis.

Quantum-improved phase estimation with a displacement-assisted SU(1,1) interferometer.

By performing two local displacement operations (LDOs) inside an SU(1,1) interferometer, called as the displacement-assisted SU(1,1) [DSU(1,1)], both the phase sensitivity based on homodyne detection and quantum Fisher information (QFI) with and without photon losses are investigated in this paper. In this DSU(1,1) interferometer, we focus our attention on the extent to which the introduced LDO affects the phase sensitivity and the QFI, even in the realistic scenario. Our analyses show that the estimation performance of DSU(1,1) interferometer is always better than that of SU(1,1) interferometer without the LDO, especially for the phase precision of the former in the ideal scenario closer to the Heisenberg limit via the increase of the LDO strength. Different from the latter, the robustness of the former can be also enhanced markedly by regulating and controlling the LDO. Our findings would open an useful view for quantum-improved phase estimation of optical interferometers.

Beam shifts controlled by orbital angular momentum in a guided-surface plasmon resonance structure with a four-level atomic medium.

We proposed a scheme to realize tunable giant Goos-Hänchen (GH) and Imbert Fedorov (IF) shifts of the Laguerre-Gauss (LG) beam on a guided-wave surface plasmon resonance (GWSPR) structure backed by a coherent atomic medium with the spontaneously generated coherence (SGC) effect. The orbital angular momentum carried by the incident LG beam can be applied to enhance and control IF shifts but is not beneficial to GH shifts. However, in the presence of SGC effect in the atomic medium, both GH and IF shifts can be simultaneously enhanced and well controlled. With the SGC effect, the linear absorption of the atomic medium vanishes, while the nonlinear absorption of that can be significantly enhanced and controlled by the trigger field, which contributes to controlling of the beam shifts. In particular, the direction of GH shifts can be switched by the Rabi frequency of the trigger field, which can be interpreted as the result of a competition between the inherent damping and the radiative damping corresponding to the nontrivial change in the loci of the reflection coefficients. This scheme provides an effective method to flexibly control and enhance the beam shifts, so it has potential applications in integrated optics, optical sensors, etc.

Tacrolimus ameliorates bleomycin-induced pulmonary fibrosis by inhibiting M2 macrophage polarization via JAK2/STAT3 signaling.

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease of unknown cause and characterized by excessive proliferation of fibroblasts and the irregular remodeling of extracellular matrix (ECM), which ultimately cause the severe distortion of the alveolar architecture. The median survival of IPF patients is 2-5 years. IPF patients are predominantly infiltrated by M2 macrophages during the course of disease development and progression. Predominantly accumulation of M2 macrophages accelerates fibrosis progression by secreting multiple cytokines that promote fibroblast to myofibroblast transition. In the process of M2 macrophage polarization, JAK2/STAT3 signaling plays a key role, thus, targeting activated macrophages to inhibit the pro-fibrotic phenotype is considered as an approach to the potential treatment of IPF. Tacrolimus is a macrolide antibiotic that as a specific inhibitor of T-lymphocyte function and has been used widely as an immunosuppressant in human organ transplantation. In this study we explored the potential effect and mechanism of tacrolimus on pulmonary fibrosis in vivo and vitro. Here, we found that tacrolimus is capable of suppressing M2 macrophages polarization by inhibiting pro-fibrotic factors secreted by M2 macrophages. This effect further alleviates M2-induced myofibroblast activation, thus resulting in a decline of collagen deposition, pro-fibrotic cytokines secretion, recovering of lung function, ultimately relieving the progression of fibrosis in vivo. Mechanistically, we found that tacrolimus can inhibit the activation of JAK2/STAT3 signaling by targeting JAK2. Our findings indicate a potential anti-fibrotic effect of tacrolimus by regulating macrophage polarization and might be meaningful in clinical settings.

Evaluating the quantum Ziv-Zakai bound for phase estimation in noisy environments.

In the highly non-Gaussian regime, the quantum Ziv-Zakai bound (QZZB) provides a lower bound on the available precision, demonstrating the better performance compared with the quantum Cramér-Rao bound. However, evaluating the impact of a noisy environment on the QZZB without applying certain approximations proposed by Tsang [Phys. Rev. Lett.108, 230401 (2012)10.1103/PhysRevLett.108.230401] remains a difficult challenge. In this paper, we not only derive the asymptotically tight QZZB for phase estimation with the photon loss and the phase diffusion by invoking the variational method and the technique of integration within an ordered product of operators, but also show its estimation performance for several different Gaussian resources, such as a coherent state (CS), a single-mode squeezed vacuum state (SMSVS) and a two-mode squeezed vacuum state (TMSVS). In this asymptotically tight situation, our results indicate that compared with the SMSVS and the TMSVS, the QZZB for the CS always shows the better estimation performance under the photon-loss environment. More interestingly, for the phase-diffusion environment, the estimation performance of the QZZB for the TMSVS can be better than that for the CS throughout a wide range of phase-diffusion strength. Our findings will provide an useful guidance for investigating the noisy quantum parameter estimation.

PKM2 promotes pulmonary fibrosis by stabilizing TGF-ß1 receptor I and enhancing TGF-ß1 signaling.

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease, and the molecular mechanisms remain poorly understood. Our findings demonstrated that pyruvate kinase M2 (PKM2) promoted fibrosis progression by directly interacting with Smad7 and reinforcing transforming growth factor-ß1 (TGF-ß1) signaling. Total PKM2 expression and the portion of the tetrameric form elevated in lungs and fibroblasts were derived from mice with bleomycin (BLM)-induced pulmonary fibrosis. Pkm2 deletion markedly alleviated BLM-induced fibrosis progression, myofibroblast differentiation, and TGF-ß1 signaling activation. Further study showed that PKM2 tetramer enhanced TGF-ß1 signaling by directly binding with Smad7 on its MH2 domain, and thus interfered with the interaction between Smad7 and TGF-ß type I receptor (TßR1), decreased TßR1 ubiquitination, and stabilized TßR1. Pharmacologically enhanced PKM2 tetramer by TEPP-46 promoted BLM-induced pulmonary fibrosis, while tetramer disruption by compound 3k alleviated fibrosis progression. Our results demonstrate how PKM2 regulates TGF-ß1 signaling and is a key factor in fibrosis progression.

Towards fine recognition of orbital angular momentum modes through smoke.

Light beams carrying orbital angular momentum (OAM) have been constantly developing in free-space optical (FSO) communications. However, perturbations in the free space link, such as rain, fog, and atmospheric turbulence, may affect the transmission efficiency of this technique. If the FSO communications procedure takes place in a smoke condition with low visibility, the communication efficiency also will be worse. Here, we use deep learning methods to recognize OAM eigenstates and superposition states in a thick smoke condition. In a smoke transmission link with visibility about 5 m to 6 m, the experimental recognition accuracy reaches 99.73% and 99.21% for OAM eigenstates and superposition states whose Bures distance is 0.05. Two 6 bit/pixel pictures were also successfully transmitted in the extreme smoke conditions. This work offers a robust and generalized proposal for FSO communications based on OAM modes and allows an increase of the communication capacity under the low visibility smoke conditions.

Lenalidomide attenuates post-inflammation pulmonary fibrosis through blocking NF-κB signaling pathway.

Idiopathic pulmonary fibrosis (IPF) is a pathological consequence of interstitial pulmonary diseases, and is characterized by the persistence of fibroblasts and excessive deposition of extracellular matrix (ECM). The etiology of IPF is multifactorial. Although the role of inflammation in fibrogenesis is controversial, it is still recognized as an important component and epiphenomenon of IPF. Stimulus increase production of pro-inflammatory cytokines and activation of NF-κB, which will further promote inflammation response and myofibroblast transition. Lenalidomide is an immunomodulatory drug. Previous studies have revealed its anti-tumor effects through regulating immune response. Here we investigate the effect of lenalidomide on post-inflammation fibrosis. In vitro study revealed that lenalidomide inhibited NF-κB signaling in LPS-induced macrophage, and further attenuated macrophage-induced myofibroblast activation. Meanwhile, lenalidomide could inhibit TGF-ß1-induced myofibroblast activation through suppressing TGF-ß1 downstream MAPK signaling. In vivo study showed that lenalidomide inhibited pro-inflammatory cytokines TNF-α and IL-6 while enhanced anti-fibrotic cytokines IFN-γ and IL-10 in bleomycin-induced inflammation model, and attenuated pulmonary fibrosis and collagen deposition in the following fibrosis stage. In conclusion, our results demonstrate that lenalidomide possesses potential anti-fibrotic effects through suppressing NF-κB signaling.

Clevudine attenuates bleomycin-induced early pulmonary fibrosis via regulating M2 macrophage polarization.

Pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease. It is a growing clinical problem which can result in breathlessness or respiratory failure and has an average life expectancy of 3 years from diagnosis. Predominantly accumulation of M2 macrophages accelerates fibrosis progression by secreting multiple cytokines that promote fibroblast to myofibroblast transition and aberrant wound healing of epithelial cells. Targeting activated macrophages to inhibit the pro-fibrotic phenotype is considered as an approach for the potential treatment of PF. Clevudine is s a purine nucleoside analogue which in an oral formulation is approved for treatment of patients with hepatitis B virus (HBV). Here, we found that clevudine is capable of suppressing pro-fibrotic phenotype (i.e., CD206, Arg1 and YM1) of M2 macrophages while enhancing anti-fibrotic phenotype (i.e., CD86, IL-6 and IL-10) by inhibiting PI3K/Akt signaling pathway. This effect further alleviates M2-induced myofibroblast activation and epithelial-to-mesenchymal transition (EMT), thus resulting in a decline of collagen deposition, pro-fibrotic cytokines secretion, with a concomitant recover ofpulmonary functions in vivo. Less infiltration of M2 macrophages between α-SMA + cells was also found in clevudine treated mice. Our findings indicate a potential anti-fibrotic effect of clevudine by regulating macrophage polarization and might be meaningful in clinical settings.

Fedratinib Attenuates Bleomycin-Induced Pulmonary Fibrosis via the JAK2/STAT3 and TGF-ß1 Signaling Pathway.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease with multiple causes, characterized by excessive myofibrocyte aggregation and extracellular matrix deposition. Related studies have shown that transforming growth factor-ß1 (TGF-ß1) is a key cytokine causing fibrosis, promoting abnormal epithelial-mesenchymal communication and fibroblast-to-myofibroblast transition. Fedratinib (Fed) is a marketed drug for the treatment of primary and secondary myelofibrosis, targeting selective JAK2 tyrosine kinase inhibitors. However, its role in pulmonary fibrosis remains unclear. In this study, we investigated the potential effects and mechanisms of Fed on pulmonary fibrosis in vitro and in vivo. In vitro studies have shown that Fed attenuates TGF-ß1- and IL-6-induced myofibroblast activation and inflammatory response by regulating the JAK2/STAT3 signaling pathway. In vivo studies have shown that Fed can reduce bleomycin-induced inflammation and collagen deposition and improve lung function. In conclusion, Fed inhibited inflammation and fibrosis processes induced by TGF-ß1 and IL-6 by targeting the JAK2 receptor.

Deglycosylated Azithromycin Attenuates Bleomycin-Induced Pulmonary Fibrosis via the TGF-ß1 Signaling Pathway.

Idiopathic pulmonary fibrosis (IPF) is a progressive, life-threatening lung disease characterized by the proliferation of myofibroblasts and deposition of extracellular matrix that results in irreversible distortion of the lung structure and the formation of focal fibrosis. The molecular mechanism of IPF is not fully understood, and there is no satisfactory treatment. However, most studies suggest that abnormal activation of transforming growth factor-ß1 (TGF-ß1) can promote fibroblast activation and epithelial to mesenchymal transition (EMT) to induce pulmonary fibrosis. Deglycosylated azithromycin (Deg-AZM) is a compound we previously obtained by removing glycosyls from azithromycin; it was demonstrated to exert little or no antibacterial effects. Here, we discovered a new function of Deg-AZM in pulmonary fibrosis. In vivo experiments showed that Deg-AZM could significantly reduce bleomycin-induced pulmonary fibrosis and restore respiratory function. Further study revealed the anti-inflammatory and antioxidant effects of Deg-AZM in vivo. In vitro experiments showed that Deg-AZM inhibited TGF-ß1 signaling, weakened the activation and differentiation of lung fibroblasts, and inhibited TGF-ß1-induced EMT in alveolar epithelial cells. In conclusion, our findings show that Deg-AZM exerts antifibrotic effects by inhibiting TGF-ß1-induced myofibroblast activation and EMT.

Betulinic acid attenuated bleomycin-induced pulmonary fibrosis by effectively intervening Wnt/ß-catenin signaling.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a fatal and progressive fibrotic lung disease lacking a validated and effective therapy. Aberrant activation of the Wnt/ß-catenin signaling cascade plays the key role in the pathogenesis of IPF. Betulinic acid is a natural pentacyclic triterpenoid molecule that has excellent antitumor and antiviral activities. HYPOTHESIS: We hypothesized that BA has an anti-pulmonary fibrosis effect mediated by the suppression of the Wnt/ß-catenin pathway. Study design Pulmonary fibrosis markers were detected in vitro and in vivo to confirm the antifibrotic effect of BA. The Wnt/ß-catenin pathway-related proteins were overexpressed to determine the effect of BA on Wnt signaling. METHODS AND RESULTS: BA dose-dependently inhibited Wnt3a-induced fibroblast activation in vitro. Moreover, BA decreased Wnt3a- and LiCl-induced transcriptional activity, as assessed by the TOPFlash assay in fibroblasts, and repressed the expression of the Wnt target genes cyclin D1, axin 2, and S100A4. Further investigation indicated that BA restrained the nuclear accumulation of ß-catenin, mainly by increasing the phospho-ß-catenin ratio (S33/S37/T41 and S45), inhibited the phosphorylation of DVL2 and LRP, and decreased the levels of Wnt3a and LRP6. In agreement with the results of the in vitro assays, the in vivo experiments indicated that BA significantly decreased bleomycin-induced pulmonary fibrosis in mice and suppressed myofibroblast activation by inhibiting Wnt/ß-catenin signaling. CONCLUSION: BA may directly interfere with the Wnt/ß-catenin pathway to subsequently repress myofibroblast activation and pulmonary fibrosis.

Myricetin ameliorates bleomycin-induced pulmonary fibrosis in mice by inhibiting TGF-ß signaling via targeting HSP90ß.

Idiopathic pulmonary fibrosis is a progressive-fibrosing lung disease with high mortality and limited therapy, which characterized by myofibroblasts proliferation and extracellular matrix deposition. Myricetin, a natural flavonoid, has been shown to possess a variety of biological characteristics including anti-inflammatory and anti-tumor. In this study we explored the potential effect and mechanisms of myricetin on pulmonary fibrosis in vivo and vitro. The in vivo studies showed that myricetin effectively alleviated bleomycin (BLM)-induced pulmonary fibrosis. KEGG analysis of RNA-seq data indicated that myricetin could regulate the transforming growth factor (TGF)-ß signaling pathway. In vitro studies indicated that myricetin could dose-dependently suppress TGF-ß1/Smad signaling and attenuate TGF-ß1-induced fibroblast activation and epithelial-mesenchymal transition (EMT). Molecular docking indicated that heat shock protein (HSP) 90ß may be a potential target of myricetin, and MST assay demonstrated that the dissociation constant (Kd) of myricetin and HSP90ß was 331.59 nM. We demonstrated that myricetin interfered with the binding of HSP90ß and TGF-ß receptor II and impeded fibroblast activation and EMT. In conclusion, myricetin impedes TGF-ß1-induced lung fibroblast activation and EMT via targeting HSP90ß and attenuates BLM-induced pulmonary fibrosis in mice.

Nintedanib Inhibits Wnt3a-Induced Myofibroblast Activation by Suppressing the Src/ß-Catenin Pathway.

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterized by epithelial cell damage, myofibroblast activation, and collagen deposition. Multiple studies have documented that the Wnt/ß-catenin pathway is aberrantly activated in IPF and plays a vital role in myofibroblast differentiation and activation. Kinases such as Src initiate Wnt/ß-catenin signaling by phosphorylating ß-catenin at tyrosine residues, which facilitates ß-catenin accumulation in the nucleus and promotion of fibrosis progression. Nintedanib has been approved for the treatment of IPF as a multitargeted tyrosine kinase inhibitor. Nintedanib has been demonstrated to directly block Src, and whether it attenuates pulmonary fibrosis through regulating the Wnt/ß-catenin pathway remains unclear. In this study, we found that nintedanib attenuated myofibroblast activation through inhibiting the expression of genes downstream of Wnt signaling such as Cyclin D1, Wisp1, and S100a4. Further experiments showed that nintedanib inhibited Wnt3a-induced ß-catenin nuclear translocation through suppressing Src kinase activation and ß-catenin Y654 phosphorylation. Additionally, Src knockdown fibroblasts exhibited a phenotype similar to that of the nintedanib treatment group, and the inhibitory effects of nintedanib were consistent with those of the Src kinase inhibitor KX2-391. In summary, our study shows that nintedanib exhibits an anti-fibrosis effect, partly by inhibiting the Src/ß-catenin pathway.

Anlotinib attenuated bleomycin-induced pulmonary fibrosis via the TGF-ß1 signalling pathway.

OBJECTIVES: Anlotinib hydrochloride (AL3818) is a novel multitarget tyrosine kinase inhibitor which has the same targets as nintedanib, an effective drug has been approved for the treatment of idiopathic pulmonary fibrosis. Here, we examined whether anlotinib could also attenuate bleomycin-induced pulmonary fibrosis in mice and explored the antifibrosis mechanism. METHODS: We have evaluated the effect of anlotinib on bleomycin-induced pulmonary fibrosis in mice. Inflammatory cytokines in alveolar lavage fluid including IL-1ß, IL-4, IL-6 and TNF-α were determined by ELISA. Biomarkers of oxidative stress were measured by corresponding kit. Histopathologic examination was analysed by H&E staining and immunohistochemistry. In vitro, we investigated whether anlotinib inhibited TGFß/Smad3 and non-Smad pathways by luciferase assay or Western blotting. We also evaluated whether anlotinib inhibited TGF-ß1-induced epithelial-mesenchymal transition (EMT) and promoted myofibroblast apoptosis in order to explore the possible molecular mechanism. KEY FINDINGS: The results indicated that anlotinib treatment remarkably attenuated inflammation, oxidative stress and pulmonary fibrosis in mouse lungs. Anlotinib could inhibit the TGF-ß1 signalling pathway. Additionally, anlotinib not only profoundly inhibited TGF-ß1-induced EMT in alveolar epithelial cells, but also simultaneously reduced the proliferation and promoted the apoptosis in fibroblasts. CONCLUSIONS: In summary, the results suggest that anlotinib-mediated suppression of pulmonary fibrosis is related to the inhibition of TGF-ß1 signalling pathway.

In vitro screening for compounds from Hypericum longistylum with anti-pulmonary fibrosis activity.

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a poor prognosis and limited therapies, and transforming growth factor-ß1 (TGF-ß1) plays a central role in the pathogenesis of IPF. Here, we aimed to investigate the chemical constituents and biological activities of Hypericum longistylum and detect whether the isolated compounds inhibit the TGF-ß1/Smad3 signaling pathway to identify candidate compounds for the treatment of pulmonary fibrosis. Fifteen compounds (1-15) were isolated from H. longistylum and their structures were elucidated on the basis of spectroscopic analyses. An in vitro MTT assay was used to test the effect of these fifteen compounds on fibroblast cytotoxicity and vitality. Furthermore, their bioactivities were screened using a TGF-ß1/Smad3 pathway luciferase reporter in vitro. MTT screening found that compounds 1-15 had no deleterious effects on normal mouse lung fibroblasts and no significant inhibition of vitality. Luciferase assay showed that compounds 14 and 15 could significantly inhibit the TGF-ß1/Smad3 pathway with the inhibition rates of 67.92% and 93.10%, respectively. Both compounds can be used as lead compounds for structural modification and optimization to obtain more drug candidates for the treatment of pulmonary fibrosis.

Antifibrotic Mechanism of Cinobufagin in Bleomycin-Induced Pulmonary Fibrosis in Mice.

Idiopathic pulmonary fibrosis (IPF) is a progressive and usually fatal lung disease that is characterized by fibroblast proliferation and extracellular matrix remodeling, which result in irreversible distortion of the lung's architecture and the formation of focal fibrous hyperplasia. The molecular mechanism by which pulmonary fibrosis develops is not fully understood, and no satisfactory treatment currently exists. However, many studies consider that aberrant activation of TGF-ß1 frequently promotes epithelial-mesenchymal transition (EMT) and fibroblast activation in pulmonary fibrosis. Cinobufagin (CBG), a traditional Chinese medicine, has been widely used for long-term pain relief, cardiac stimulation, and anti-inflammatory and local anesthetic treatments. However, its role in pulmonary fibrosis has not yet been established. We investigated the hypothesis that cinobufagin plays an inhibitory role on TGF-ß1 signaling using a luciferase-reporter assay. We further explored the effect of cinobufagin on pulmonary fibrosis both in vitro and in vivo. The in vitro experiments showed that cinobufagin suppresses TGF-ß1/Smad3 signaling in a dose-dependent manner, attenuates the activation and differentiation of lung fibroblasts and inhibits EMT induced by TGF-ß1 in alveolar epithelial cells. The in vivo experiments indicated that cinobufagin significantly alleviates bleomycin-induced collagen deposition and improves pulmonary function. Further study showed that cinobufagin could attenuate bleomycin-induced inflammation and inhibit fibroblast activation and the EMT process in vivo. In summary, cinobufagin attenuates bleomycin-induced pulmonary fibrosis in mice via suppressing inflammation, fibroblast activation and epithelial-mesenchymal transition.