scholarly journals Azithromycin Attenuates Bleomycin-Induced Pulmonary Fibrosis Partly by Inhibiting the Expression of LOX and LOXL-2

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiang Tong ◽  
Shijie Zhang ◽  
Dongguang Wang ◽  
Li Zhang ◽  
Jizheng Huang ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Signaling Pathways ◽  
Lung Tissue ◽  
Type I Collagen ◽  
Lysyl Oxidase ◽  
Specific Inhibitor ◽  
Lung Fibroblasts ◽  
Type I ◽  
Primary Mouse ◽  
Tgf Β1

Pulmonary fibrosis (PF) is a chronic and progressive process of tissue repair. Azithromycin (AZM) may be beneficial for the treatment of PF because AZM has anti-inflammatory and immune regulatory roles and inhibits remodeling, but the mechanism is not entirely clear. In this study, we established a mouse PF model induced by bleomycin (BLM) and primary mouse lung fibroblasts stimulated by transforming growth factor (TGF)-β1 to explore the possible mechanisms of AZM in PF. Results showed that AZM reduces mortality and lung inflammation and attenuates BLM-induced PF in mice. AZM effectively reduced the expression of α-smooth muscle actin (SMA) and type I collagen. Meanwhile, expression of lysyl oxidase (LOX) and lysyl oxidase-like protein (LOXL)-2 in the lung tissue of mice after AZM treatment was significantly lower than in the BLM group. In addition, this study found that AZM significantly inhibits the TGF-β1/Smad and JNK/c-Jun signaling pathways in vivo, and expression of a-SMA, type I collagen, LOX and LOXL-2 in the lung tissue of mice treated with AZM was significantly lower than that in the BLM group. In vitro, AZM also effectively inhibited type I collagen, LOX, LOXL-2 and JNK-c-Jun signaling pathways in TGF-β1-stimulated primary mouse fibroblasts, and this effect was similar to that of a JNK-specific inhibitor (SP600125). In conclusion, AZM effectively attenuated BLM-induced PF in mice, which may play a role by partially inhibiting the JNK/c-Jun and TGF-β1/Smad signaling pathways and reducing production of LOX and LOXL2.

scholarly journals Pathological integrin signaling enhances proliferation of primary lung fibroblasts from patients with idiopathic pulmonary fibrosis

2008 ◽  
Vol 205 (7) ◽  
pp. 1659-1672 ◽  
Author(s):  
Hong Xia ◽  
Deanna Diebold ◽  
Richard Nho ◽  
David Perlman ◽  
Jill Kleidon ◽  
...  
Keyword(s):  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Type I Collagen ◽  
Tissue Injury ◽  
Signal Pathway ◽  
Lung Fibroblasts ◽  
Integrin Signaling ◽  
Type I ◽  
Β1 Integrin ◽  
Fibroblast Proliferation

Idiopathic pulmonary fibrosis (IPF) is a relentlessly progressive lung disease in which fibroblasts accumulate in the alveolar wall within a type I collagen–rich matrix. Although lung fibroblasts derived from patients with IPF display durable pathological alterations in proliferative function, the molecular mechanisms differentiating IPF fibroblasts from their normal counterparts remain unknown. Polymerized type I collagen normally inhibits fibroblast proliferation, providing a physiological mechanism to limit fibroproliferation after tissue injury. We demonstrate that β1 integrin interaction with polymerized collagen inhibits normal fibroblast proliferation by suppression of the phosphoinositide 3-kinase (PI3K)–Akt–S6K1 signal pathway due to maintenance of high phosphatase activity of the tumor suppressor phosphatase and tensin homologue (PTEN). In contrast, IPF fibroblasts eluded this restraint, displaying a pathological pattern of β1 integrin signaling in response to polymerized collagen that leads to aberrant activation of the PI3K–Akt–S6K1 signal pathway caused by inappropriately low PTEN activity. Mice deficient in PTEN showed a prolonged fibroproliferative response after tissue injury, and immunohistochemical analysis of IPF lung tissue demonstrates activation of Akt in cells within fibrotic foci. These results provide direct evidence for defective negative regulation of the proliferative pathway in IPF fibroblasts and support the theory that the pathogenesis of IPF involves an intrinsic fibroblast defect.

PPARγ agonists inhibit TGF-β induced pulmonary myofibroblast differentiation and collagen production: implications for therapy of lung fibrosis

2005 ◽  
Vol 288 (6) ◽  
pp. L1146-L1153 ◽  
Author(s):  
Heather A. Burgess ◽  
Louis Eugene Daugherty ◽  
Thomas H. Thatcher ◽  
Heather F. Lakatos ◽  
Denise M. Ray ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Target Genes ◽  
Type I Collagen ◽  
Smooth Muscle Actin ◽  
Dominant Negative ◽  
Lung Fibroblasts ◽  
Peroxisome Proliferator ◽  
Type I ◽  
Myofibroblast Differentiation ◽  
Pparγ Agonists

Pulmonary fibrosis is a progressive life-threatening disease for which no effective therapy exists. Myofibroblasts are one of the key effector cells in pulmonary fibrosis and are the primary source of extracellular matrix production. Drugs that inhibit the differentiation of fibroblasts to myofibroblasts have potential as antifibrotic therapies. Peroxisome proliferator-activated receptor (PPAR)-γ is a transcription factor that upon ligation with PPARγ agonists activates target genes containing PPAR response elements. PPARγ agonists have anti-inflammatory activities and may have potential as antifibrotic agents. In this study, we examined the abilities of PPARγ agonists to block two of the most important profibrotic activities of TGF-β on pulmonary fibroblasts: myofibroblast differentiation and production of excess collagen. Both natural (15d-PGJ2) and synthetic (ciglitazone and rosiglitazone) PPARγ agonists inhibited TGF-β-driven myofibroblast differentiation, as determined by α-smooth muscle actin-specific immunocytochemistry and Western blot analysis. PPARγ agonists also potently attenuated TGF-β-driven type I collagen protein production. A dominant-negative PPARγ partially reversed the inhibition of myofibroblast differentiation by 15d-PGJ2 and rosiglitazone, but the irreversible PPARγ antagonist GW-9662 did not, suggesting that the antifibrotic effects of the PPARγ agonists are mediated through both PPARγ-dependent and independent mechanisms. Thus PPARγ agonists have novel and potent antifibrotic effects in human lung fibroblasts and may have potential for therapy of fibrotic diseases in the lung and other tissues.

scholarly journals TGF-β1 stimulates human AT1 receptor expression in lung fibroblasts by cross talk between the Smad, p38 MAPK, JNK, and PI3K signaling pathways

2007 ◽  
Vol 293 (3) ◽  
pp. L790-L799 ◽  
Author(s):  
Mickey M. Martin ◽  
Jessica A. Buckenberger ◽  
Jinmai Jiang ◽  
Geraldine E. Malana ◽  
Daren L. Knoell ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Pulmonary Fibrosis ◽  
Signaling Pathways ◽  
P38 Mapk ◽  
Lung Fibroblasts ◽  
Pi3k Signaling ◽  
R Gene ◽  
Ang Ii ◽  
Tgf Β1

Both angiotensin II (ANG II) and transforming growth factor-β1 (TGF-β1) are thought to be involved in mediating pulmonary fibrosis. Interactions between the renin-angiotensin system (RAS) and TGF-β1 have been well documented, with most studies describing the effect of ANG II on TGF-β1 expression. However, recent gene expression profiling experiments demonstrated that the angiotensin II type 1 receptor (AT1R) gene was a novel TGF-β1 target in human adult lung fibroblasts. In this report, we show that TGF-β1 augments human AT1R (hAT1R) steady-state mRNA and protein levels in a dose- and time-dependent manner in primary human fetal pulmonary fibroblasts (hPFBs). Nuclear run-on experiments demonstrate that TGF-β1 transcriptionally activates the hAT1R gene and does not influence hAT1R mRNA stability. Pharmacological inhibitors and specific siRNA knockdown experiments demonstrate that the TGF-β1 type 1 receptor (TβRI/ALK5), Smad2/3, and Smad4 are essential for TGF-β1-stimulated hAT1R expression. Additional pharmacological inhibitor and small interference RNA experiments also demonstrated that p38 MAPK, JNK, and phosphatidylinositol 3-kinase (PI3K) signaling pathways are also involved in the TGF-β1-stimulated increase in hAT1R density. Together, our results suggest an important role for cross talk among Smad, p38 MAPK, JNK, and PI3K pathways in mediating the augmented expression of hAT1R following TGF-β1 treatment in hPFB. This study supports the hypothesis that a self-potentiating loop exists between the RAS and the TGF-β1 signaling pathways and suggests that ANG II and TGF-β1 may cooperate in the pathogenesis of pulmonary fibrosis. The synergy between these systems may require that both pathways be simultaneously inhibited to treat fibrotic lung disease.

TRIM33 prevents pulmonary fibrosis by impairing TGF-β1 signalling

2020 ◽  
Vol 55 (6) ◽  
pp. 1901346 ◽  
Author(s):  
Pierre-Marie Boutanquoi ◽  
Olivier Burgy ◽  
Guillaume Beltramo ◽  
Pierre-Simon Bellaye ◽  
Lucile Dondaine ◽  
...  
Keyword(s):  
Pulmonary Fibrosis ◽  
Lung Tissue ◽  
Transforming Growth Factor ◽  
Small Heat Shock Protein ◽  
Negative Regulator ◽  
Lung Fibroblasts ◽  
Tissue Slices ◽  
Tgf Β1

BackgroundIdiopathic pulmonary fibrosis (IPF) is a devastating disease characterised by myofibroblast proliferation and abnormal extracellular matrix accumulation in the lungs. Transforming growth factor (TGF)-β1 initiates key profibrotic signalling involving the SMAD pathway and the small heat shock protein B5 (HSPB5). Tripartite motif-containing 33 (TRIM33) has been reported to negatively regulate TGF-β/SMAD signalling, but its role in fibrogenesis remains unknown. The objective of this study was to elucidate the role of TRIM33 in IPF.MethodsTRIM33 expression was assessed in the lungs of IPF patients and rodent fibrosis models. Bone marrow-derived macrophages (BMDM), primary lung fibroblasts and 3D lung tissue slices were isolated from Trim33-floxed mice and cultured with TGF-β1 or bleomycin (BLM). Trim33 expression was then suppressed by adenovirus Cre recombinase (AdCre). Pulmonary fibrosis was evaluated in haematopoietic-specific Trim33 knockout mice and in Trim33-floxed mice that received AdCre and BLM intratracheally.ResultsTRIM33 was overexpressed in alveolar macrophages and fibroblasts in IPF patients and rodent fibrotic lungs. Trim33 inhibition in BMDM increased TGF-β1 secretion upon BLM treatment. Haematopoietic-specific Trim33 knockout sensitised mice to BLM-induced fibrosis. In primary lung fibroblasts and 3D lung tissue slices, Trim33 deficiency increased expression of genes downstream of TGF-β1. In mice, AdCre-Trim33 inhibition worsened BLM-induced fibrosis. In vitro, HSPB5 was able to bind directly to TRIM33, thereby diminishing its protein level and TRIM33/SMAD4 interaction.ConclusionOur results demonstrate a key role of TRIM33 as a negative regulator of lung fibrosis. Since TRIM33 directly associates with HSPB5, which impairs its activity, inhibitors of TRIM33/HSPB5 interaction may be of interest in the treatment of IPF.

scholarly journals Autophagy Promotes Intracellular Degradation of Type I Collagen Induced by Transforming Growth Factor (TGF)-β1

2012 ◽  
Vol 287 (15) ◽  
pp. 11677-11688 ◽  
Author(s):  
Sung Il Kim ◽  
Hee-Jun Na ◽  
Yan Ding ◽  
Zhibo Wang ◽  
Seon Jin Lee ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Mesangial Cells ◽  
Beclin 1 ◽  
Type I ◽  
Protein Levels ◽  
Intracellular Degradation ◽  
Primary Mouse ◽  
Tgf Β1

Autophagy is a highly conserved cellular process regulating turnover of cytoplasmic proteins via a lysosome-dependent pathway. Here we show that kidneys from mice deficient in autophagic protein Beclin 1 exhibited profibrotic phenotype, with increased collagen deposition. Reduced Beclin 1 expression, through genetic disruption of beclin 1 or knockdown by specific siRNA in primary mouse mesangial cells (MMC), resulted in increased protein levels of type I collagen (Col-I). Inhibition of autolysosomal protein degradation by bafilomycin A1 also increased Col-I protein levels and colocalization of Col-I with LC3, an autophagy marker, or LAMP-1, a lysosome marker, whereas treatment with TFP, an inducer of autophagy, resulted in decreased Col-I protein levels induced by TGF-β1, without alterations in Col-I α1 mRNA. Heterozygous deletion of beclin 1 increased accumulation of aggregated Col-I under nonstimulated conditions, and stimulation with TGF-β1 further increased aggregated Col-I. These data indicate that Col-I and aggregated, insoluble procollagen I undergo intracellular degradation via autophagy. A cytoprotective role of autophagy is implicated in kidney injury, and we demonstrate that low-dose carbon monoxide, shown to exert cytoprotection against renal fibrosis, induces autophagy to suppress accumulation of Col-I induced by TGF-β1. We also show that TGF-β1 induces autophagy in MMC via TAK1-MKK3-p38 signaling pathway. The dual functions of TGF-β1, as both an inducer of Col-I synthesis and an inducer of autophagy and Col-I degradation, underscore the multifunctional nature of TGF-β1. Our findings suggest a novel role of autophagy as a cytoprotective mechanism to negatively regulate and prevent excess collagen accumulation in the kidney.

scholarly journals Interdependence of HIF-1α and TGF-β/Smad3 signaling in normoxic and hypoxic renal epithelial cell collagen expression

2011 ◽  
Vol 300 (4) ◽  
pp. F898-F905 ◽  
Author(s):  
Rajit K. Basu ◽  
Susan Hubchak ◽  
Tomoko Hayashida ◽  
Constance E. Runyan ◽  
Paul T. Schumacker ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Renal Fibrosis ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Dominant Negative ◽  
Type I ◽  
Mrna Levels ◽  
Renal Epithelial Cell ◽  
Collagen Expression ◽  
Tgf Β1

Increasing evidence suggests that chronic kidney disease may develop following acute kidney injury and that this may be due, in part, to hypoxia-related phenomena. Hypoxia-inducible factor (HIF) is stabilized in hypoxic conditions and regulates multiple signaling pathways that could contribute to renal fibrosis. As transforming growth factor (TGF)-β is known to mediate renal fibrosis, we proposed a profibrotic role for cross talk between the TGF-β1 and HIF-1α signaling pathways in kidney cells. Hypoxic incubation increased HIF-1α protein expression in cultured human renal tubular epithelial cells and mouse embryonic fibroblasts. TGF-β1 treatment further increased HIF-1α expression in cells treated with hypoxia and also increased HIF-1α in normoxic conditions. TGF-β1 did not increase HIF-1α mRNA levels nor decrease the rate of protein degradation, suggesting that it enhances normoxic HIF-1α translation. TGF-β receptor (ALK5) kinase activity was required for increased HIF-1α expression in response to TGF-β1, but not to hypoxia. A dominant negative Smad3 decreased the TGF-β-stimulated reporter activity of a HIF-1α-sensitive hypoxia response element. Conversely, a dominant negative HIF-1α construct decreased Smad-binding element promoter activity in response to TGF-β. Finally, blocking HIF-1α transcription with a biochemical inhibitor, a dominant negative construct, or gene-specific knockdown decreased basal and TGF-β1-stimulated type I collagen expression, while HIF-1α overexpression increased both. Taken together, our data demonstrate cooperation in signaling between Smad3 and HIF-1α and suggest a new paradigm in which HIF-1α is necessary for normoxic, TGF-β1-stimulated renal cell fibrogenesis.

scholarly journals Abrogation of TGF-β1-induced fibroblast-myofibroblast differentiation by histone deacetylase inhibition

2009 ◽  
Vol 297 (5) ◽  
pp. L864-L870 ◽  
Author(s):  
Weichao Guo ◽  
Bin Shan ◽  
Ross C. Klingsberg ◽  
Xiangmei Qin ◽  
Joseph A. Lasky
Keyword(s):  
Histone Deacetylase ◽  
Type I Collagen ◽  
Transforming Growth Factor ◽  
Trichostatin A ◽  
Lung Fibroblasts ◽  
Type I ◽  
Myofibroblast Differentiation ◽  
Dependent Manner ◽  
Mrna Induction ◽  
Tgf Β1

Idiopathic pulmonary fibrosis (IPF) is a devastating disease with no known effective pharmacological therapy. The fibroblastic foci of IPF contain activated myofibroblasts that are the major synthesizers of type I collagen. Transforming growth factor (TGF)-β1 promotes differentiation of fibroblasts into myofibroblasts in vitro and in vivo. In the current study, we investigated the molecular link between TGF-β1-mediated myofibroblast differentiation and histone deacetylase (HDAC) activity. Treatment of normal human lung fibroblasts (NHLFs) with the pan-HDAC inhibitor trichostatin A (TSA) inhibited TGF-β1-mediated α-smooth muscle actin (α-SMA) and α1 type I collagen mRNA induction. TSA also blocked the TGF-β1-driven contractile response in NHLFs. The inhibition of α-SMA expression by TSA was associated with reduced phosphorylation of Akt, and a pharmacological inhibitor of Akt blocked TGF-β1-mediated α-SMA induction in a dose-dependent manner. HDAC4 knockdown was effective in inhibiting TGF-β1-stimulated α-SMA expression as well as the phosphorylation of Akt. Moreover, the inhibitors of protein phosphatase 2A and 1 (PP2A and PP1) rescued the TGF-β1-mediated α-SMA induction from the inhibitory effect of TSA. Together, these data demonstrate that the differentiation of NHLFs to myofibroblasts is HDAC4 dependent and requires phosphorylation of Akt.

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