Reprogramming of Profibrotic Macrophages for Treatment of Bleomycin-Induced Pulmonary Fibrosis
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ABSTRACT:
SUBMITTER: Dr. Fenghua Zhang
PROVIDER: S-SCDT-EMM-2020-12034 | biostudies-other |
REPOSITORIES: biostudies-other
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Project description:Fibrotic diseases cause organ failure that lead to ~45% of all deaths in the United States. Activated macrophages stimulate fibrosis by secreting cytokines that induce fibroblasts to synthesize collagen and extracellular matrix proteins. Although suppression of macrophage-derived cytokine production can halt progression of fibrosis, therapeutic agents that prevent release of these cytokines (e.g., TLR7 agonists) have proven too toxic to administer systemically. Based on the expression of folate receptor β solely on activated myeloid cells, we have created a folate-targeted TLR7 agonist (FA-TLR7-54) that selectively accumulates in profibrotic macrophages and suppresses fibrosis-inducing cytokine production. We demonstrate that FA-TLR7-54 reprograms M2-like fibrosis-inducing macrophages into fibrosis-suppressing macrophages, resulting in dramatic declines in profibrotic cytokine release, hydroxyproline biosynthesis, and collagen deposition, with concomitant increases in alveolar airspaces. Although nontargeted TLR7-54 is lethal at fibrosis-suppressing doses, FA-TLR7-54 halts fibrosis without evidence of toxicity. Taken together, FA-TLR7-54 is shown to constitute a novel and potent approach for treating fibrosis without causing dose-limiting systemic toxicities.
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Project description:Patients with pulmonary fibrosis often have low vitamin D levels, the effects of which are largely unknown. We here report that early vitamin D supplementation significantly reduced the severity of pulmonary fibrosis and inflammatory cell accumulationin in the bleomycin-induced pulmonary fibrosis mouse model on supplementary days 14, 21 and 28 (P < 0.001). Vitamin D supplementation also prevented some ultrastructural changes in response to bleomycin administration, including basement membrane thickening, interstitial fibrin deposition and microvilli flattening or disappearance on days 14, 21 and 28, and lamellar body swelling or vacuolation on days 21 and 28. The bleomycin group had rising hydroxyproline level on days 14, 21 and 28, whereas the vitamin D treatment group showed consistently lower hydroxyproline level but still higher than that of the control group (P < 0.001). Our immunohistochemistry and densitometry analyses showed less staining for α-smooth muscle actin, a myofibroblast marker, in the vitamin D group compared to the bleomycin group (P < 0.001). Thus, vitamin D treatment could prevent bleomycin-induced pulmonary fibrosis by delaying or suppressing ultrastructural changes, as well as attenuating hydroxyproline accumulation and inhibiting myofibroblastic proliferation. These data further our understanding of the roles of vitamin D in pulmonary fibrogenesis and in the treatment of pulmonary fibrosis.
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Project description:Pulmonary fibrosis therapy is limited by the unclear mechanism of its pathogenesis. C57BL/6 mice were used to construct the pulmonary fibrosis model in this study. The results showed that Men1, which encodes menin protein, was significantly downregulated in bleomycin (BLM)-induced pulmonary fibrosis. Mice were made to overexpress or had Men1 knockdown with adeno-associated virus (AAV) infection and then induced with pulmonary fibrosis. BLM-induced pulmonary fibrosis was attenuated by Men1 overexpression and exacerbated by Men1 knockdown. Further analysis revealed the distinct roles of Men1 in fibroblasts and macrophages. Men1 inhibited fibroblast activation and extracellular matrix (ECM) protein expression while promoting macrophages to be profibrotic (M2) phenotype and enhancing their migration. Accordingly, pyroptosis was potentiated by Men1 in mouse peritoneal macrophages (PMCs) and lung tissues upon BLM stimulation. Furthermore, the expression of profibrotic factor OPN was positively regulated by menin in Raw264.7 cells and lung tissues by binding to the OPN promoter region. Taken together, although Men1 showed antifibrotic properties in BLM-induced pulmonary fibrosis mice, conflictive roles of Men1 were displayed in fibroblasts and macrophages. The profibrotic role of Men1 in macrophages may occur via the regulation of macrophage pyroptosis and OPN expression. This study extends the current pathogenic understanding of pulmonary fibrosis.
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Project description:The pathological hallmark lesions in idiopathic pulmonary fibrosis are the fibroblastic foci, in which fibroblasts are thought to be involved in the tissue remodeling, matrix deposition, and cross-talk with alveolar epithelium. Recent evidence indicates that some fibroblasts in fibrosis may be derived from bone marrow progenitors as well as from epithelial cells through epithelial-mesenchymal transition. To evaluate whether endothelial cells could represent an additional source for fibroblasts, bleomycin-induced lung fibrosis was established in Tie2-Cre/CAG-CAT-LacZ double-transgenic mice, in which LacZ was stably expressed in pan-endothelial cells. Combined X-gal staining and immunocytochemical staining for type I collagen and alpha-smooth muscle actin revealed the presence of X-gal-positive cells in lung fibroblast cultures from bleomycin-treated mice. To explore the underlying mechanisms, by which loss of endothelial-specific markers and gain of mesenchymal phenotypes could be involved in microvascular endothelial cells, the effects of activated Ras and TGF-beta on the microvascular endothelial cell line MS1 were analyzed. Combined treatment with activated Ras and TGF-beta caused a significant loss of endothelial-specific markers, while inducing de novo mesenchymal phenotypes. The altered expression of these markers in MS1 cells with activated Ras persisted after withdrawal of TGF-beta in vitro and in vivo. These findings are the first to show that lung capillary endothelial cells could give rise to significant numbers of fibroblasts through an endothelial-mesenchymal transition in bleomycin-induced lung fibrosis model.
| S-EPMC2937229 | biostudies-literature
Project description:The progression of pulmonary fibrosis (PF) entails a complex network of interactions between multiple classes of molecules and cells, which are closely related to the vagus nerve. Stimulation of the vagus nerve increases fibrogenic cytokines in humans, therefore, activation of the nerve may promote PF. The hypothesis was tested by comparing the extent and severity of fibrosis in lungs with and without vagal innervation in unilaterally vagotomized mice. The results show that in vagotomized lungs, there were less collagen staining, less severe fibrotic foci (subpleural, peri-vascular and peri-bronchiolar lesions) and destruction of alveolar architecture; decreased collagen deposition (denervated vs intact: COL1α1, 19.1 ± 2.2 vs 22.0 ± 2.6 ng/mg protein; COL1α2, 4.5 ± 0.3 vs 5.7 ± 0.5 ng/mg protein; p < 0.01, n = 21) and protein levels of transforming growth factor beta and interleukin 4; and fewer myofibroblast infiltration (denervated vs intact: 1.2 ± 0.2 vs 3.2 ± 0.6 cells/visual field; p < 0.05, n = 6) and M2 macrophages [though the infiltration of macrophages was increased (denervated vs intact: 112 ± 8 vs 76 ± 9 cells/visual field; p < 0.01, n = 6), the percentage of M2 macrophages was decreased (denervated vs intact: 31 ± 4 vs 57 ± 9%; p < 0.05, n = 5)]. It indicated that the vagus nerve may influence PF by enhancing fibrogenic factors and fibrogenic cells.
| S-EPMC4542162 | biostudies-other
Project description:BackgroundPulmonary fibrosis is a progressive and lethal disease characterized by damage to the lung parenchyma with excess extracellular matrix deposition. The involvement of endothelial cells in fibrosis development is unclear.MethodsWe isolated pulmonary endothelial cells, using a magnetic-activated cell sorting system, from mice with pulmonary fibrosis induced by intratracheal bleomycin. We characterized endothelial cells isolated at various times in the course of pulmonary fibrosis development.ResultsInflammatory cell infiltration was observed at 7 days after bleomycin administration, and fibrotic changes with increased collagen content were observed on day 21. Endothelial cells were isolated at these two timepoints. Levels of von Willebrand factor, plasminogen activator inhibitor-1 and matrix metalloproteinase-12 were elevated in lung endothelial cells isolated from bleomycin-treated mice at days 7 and 21. This indicated that intratracheal bleomycin administration induced endothelium injury. Expression of fibrogenic mediators, transforming growth factor (TGF)-β, connective tissue growth factor and platelet-derived growth factor-C was elevated in the cells from bleomycin-treated, compared with untreated, lungs. When endothelial cells were treated with TGF-β, α-smooth muscle actin (SMA) expression and collagen production were increased only in those cells from bleomycin-treated mouse lungs. Thapsigargin-induced prostaglandin I2 and nitric oxide production, decreased in endothelial cells from bleomycin-treated mouse lungs, compared with controls, was further suppressed by TGF-β.ConclusionBleomycin administration induced functional changes in lung endothelial cells, indicating potential involvement of endothelium in pulmonary fibrogenesis.
| S-EPMC6019800 | biostudies-literature
Project description:Pulmonary fibrosis is a chronic and irreversible scarring disease in the lung with poor prognosis. Few therapies are available; therefore it is critical to identify new therapeutic targets. Our lab has previously identified the enzyme lactate dehydrogenase-A (LDHA) as a potential therapeutic target in pulmonary fibrosis. We found increases in LDHA protein and its metabolic product, lactate, in patients with idiopathic pulmonary fibrosis (IPF). Importantly, we described lactate as a novel pro-fibrotic mediator by acidifying the extracellular space, and activating latent transforming growth factor beta (TGF-β1) in a pH-dependent manner. We propose a pro-fibrotic feed-forward loop by which LDHA produces lactate, lactate decreases pH in the extracellular space and activates TGF-β1 which can further perpetuate fibrotic signaling. Our previous work also demonstrates that the LDHA inhibitor gossypol inhibits TGF-β1-induced myofibroblast differentiation and collagen production in vitro. Here, we employed a mouse model of bleomycin-induced pulmonary fibrosis to test whether gossypol inhibits pulmonary fibrosis in vivo. We found that gossypol dose-dependently inhibits bleomycin-induced collagen accumulation and TGF-β1 activation in mouse lungs when treatment is started on the same day as bleomycin administration. Importantly, gossypol was also effective at treating collagen accumulation when delayed 7 days following bleomycin. Our results demonstrate that inhibition of LDHA with the inhibitor gossypol is effective at both preventing and treating bleomycin-induced pulmonary fibrosis, and suggests that LDHA may be a potential therapeutic target for pulmonary fibrosis.
| S-EPMC5967738 | biostudies-literature
Project description:Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease, wherein transforming growth factor ? (TGF-?) and sphingosine-1-phosphate (S1P) contribute to the pathogenesis of fibrosis. However, the in vivo contribution of sphingosine kinase (SphK) in fibrotic processes has not been documented. Microarray analysis of blood mononuclear cells from patients with IPF and SphK1- or SphK2-knockdown mice and SphK inhibitor were used to assess the role of SphKs in fibrogenesis. The expression of SphK1/2 negatively correlated with lung function and survival in patients with IPF. Also, the expression of SphK1 was increased in lung tissues from patients with IPF and bleomycin-challenged mice. Knockdown of SphK1, but not SphK2, increased survival and resistance to pulmonary fibrosis in bleomycin-challenged mice. Administration of SphK inhibitor reduced bleomycin-induced mortality and pulmonary fibrosis in mice. Knockdown of SphK1 or treatment with SphK inhibitor attenuated S1P generation and TGF-? secretion in a bleomycin-induced lung fibrosis mouse model that was accompanied by reduced phosphorylation of Smad2 and MAPKs in lung tissue. In vitro, bleomycin-induced expression of SphK1 in lung fibroblast was found to be TGF-? dependent. Taken together, these data indicate that SphK1 plays a critical role in the pathology of lung fibrosis and is a novel therapeutic target.
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Project description:BACKGROUND: Antiflammin-1 (AF-1), a derivative of uteroglobin (UG), is a synthetic nonapeptide with diverse biological functions. In the present study, we investigated whether AF-1 has a protective effect against bleomycin-induced pulmonary fibrosis. METHODS: C57BL/6 mice were injected with bleomycin intratracheally to create an animal model of bleomycin-induced pulmonary fibrosis. On Day 7 and Day 28, we examined the anti-inflammatory effect and antifibrotic effect, respectively, of AF-1 on the bleomycin-treated mice. The effects of AF-1 on the transforming growth factor-beta 1 (TGF-?1)-induced proliferation of murine lung fibroblasts (NIH3T3) were examined by a bromodeoxycytidine (BrdU) incorporation assay and cell cycle analysis. RESULTS: Severe lung inflammation and fibrosis were observed in the bleomycin-treated mice on Day 7 and Day 28, respectively. Administration of AF-1 significantly reduced the number of neutrophils in the bronchoalveolar lavage fluid (BALF) and the levels of tumor necrosis factor-alpha (TNF-?) and interleukin-1 beta (IL-1?) in the lung homogenates on Day 7. Histological examination revealed that AF-1 markedly reduced the number of infiltrating cells on Day 7 and attenuated the collagen deposition and destruction of lung architecture on Day 28. The hydroxyproline (HYP) content was significantly decreased in the AF-1-treated mice. In vitro, AF-1 inhibited the TGF-?1-induced proliferation of NIH3T3 cells, which was mediated by the UG receptor. CONCLUSIONS: AF-1 has anti-inflammatory and antifibrotic actions in bleomycin-induced lung injury. We propose that the antifibrotic effect of AF-1 might be related to its suppression of fibroblast growth in bleomycin-treated lungs and that AF-1 has potential as a new therapeutic tool for pulmonary fibrosis.
| S-EPMC3856527 | biostudies-literature
Project description:Notch signaling pathway is involved in the regulation of cell fate, differentiation, proliferation, and apoptosis in development and disease. Previous studies suggest the importance of Notch1 in myofibroblast differentiation in lung alveogenesis and fibrosis. However, direct in vivo evidence of Notch1-mediated myofibroblast differentiation is lacking. In this study, we examined the effects of conditional mesenchymal-specific deletion of Notch1 on pulmonary fibrosis. Crossing of mice bearing the floxed Notch1 gene with ?2(I) collagen enhancer-Cre-ER(T)-bearing mice successfully generated progeny with a conditional knockout (CKO) of Notch1 in collagen I-expressing (mesenchymal) cells on treatment with tamoxifen (Notch1 CKO). Because Notch signaling is known to be activated in the bleomycin model of pulmonary fibrosis, control and Notch1 CKO mice were analyzed for their responses to bleomycin treatment. The results showed significant attenuation of pulmonary fibrosis in CKO relative to control mice, as examined by collagen deposition, myofibroblast differentiation, and histopathology. However, there were no significant differences in inflammatory or immune cell influx between bleomycin-treated CKO and control mouse lungs. Analysis of isolated lung fibroblasts confirmed absence of Notch1 expression in cells from CKO mice, which contained fewer myofibroblasts and significantly diminished collagen I expression relative to those from control mice. These findings revealed an essential role for Notch1-mediated myofibroblast differentiation in the pathogenesis of pulmonary fibrosis.
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