The role of ILâ 5 in bleomycinâ induced pulmonary fibrosis

Eosinophils are known to express cytokines capable of promoting fibrosis. Interleukinâ 5 (ILâ 5) is important in regulating eosinophilopoiesis, eosinophil recruitment and activation. Lung ILâ 5 expression is elevated in pulmonary fibrosis, wherein the eosinophil is a primary source of fibrogenic cytokines. To determine the role of ILâ 5 in pulmonary fibrosis, the effects of antiâ ILâ 5 antibody were investigated in a model of bleomycinâ induced pulmonary fibrosis. Fibrosis was induced in mice by endotracheal bleomycin treatment. Animals were also treated with either antiâ ILâ 5 antibody or control IgG. Lungs were then analyzed for fibrosis, eosinophil influx, chemotactic activity, and cytokine expression. The results show that a primary chemotactic activity at the height of eosinophil recruitment is ILâ 5. Furthermore, antiâ ILâ 5 antibody caused significant reduction in lung eosinophilia, cytokine expression, and fibrosis. These findings taken together suggest an important role for ILâ 5 in pulmonary fibrosis via its ability to regulate eosinophilic inflammation, and thus eosinophilâ dependent fibrogenic cytokine production. J. Leukoc. Biol. 64: 657â 666; 1998.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141191/1/jlb0657.pd

Obesity‐induced diabetes and lower urinary tract fibrosis promote urinary voiding dysfunction in a mouse model

BACKGROUND Progressive aging‐ and inflammation‐associated fibrosis effectively remodels the extracellular matrix (ECM) to increase prostate tissue stiffness and reduce urethral flexibility, resulting in urinary flow obstruction and lower urinary tract symptoms (LUTS). In the current study, we sought to test whether senescence‐accelerated mouse prone (SAMP)6 mice, which were reported to develop prostatic fibrosis, would also develop LUTS, and whether these symptoms would be exacerbated by diet‐induced obesity and concurrent Type 2 Diabetes Mellitus (T2DM). METHODS To accomplish this, SAMP6 and AKR/J background strain mice were fed regular mouse chow, low fat diet chow, or high fat diet chow for 8 months, then subjected to glucose tolerance tests, assessed for plasma insulin levels, evaluated for urinary voiding function, and assessed for lower urinary tract fibrosis. RESULTS The results of these studies show that SAMP6 mice and AKR/J background strain mice develop diet‐induced obesity and T2DM concurrent with urinary voiding dysfunction. Moreover, urinary voiding dysfunction was more severe in SAMP6 than AKR/J mice and was associated with pronounced prostatic and urethral tissue fibrosis. CONCLUSIONS Taken together, these studies suggest that obesity, T2DM, lower urinary tract fibrosis, and urinary voiding dysfunction are inextricably and biologically linked. Prostate 73: 1123–1133, 2013. © 2013 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98367/1/22662_ftp.pd

Edar is a downstream target of beta-catenin and drives collagen accumulation in the mouse prostate

Beta-catenin (CTNNB1) directs ectodermal appendage spacing by activating ectodysplasin A receptor (EDAR) transcription, but whether CTNNB1 acts by a similar mechanism in the prostate, an endoderm-derived tissue, is unclear. Here we examined the expression, function, and CTNNB1 dependence of the EDAR pathway during prostate development. In situ hybridization studies reveal EDAR pathway components including Wnt10b in the developing prostate and localize these factors to prostatic bud epithelium where CTNNB1 target genes are co-expressed. We used a genetic approach to ectopically activate CTNNB1 in developing mouse prostate and observed focal increases in Edar and Wnt10b mRNAs. We also used a genetic approach to test the prostatic consequences of activating or inhibiting Edar expression. Edar overexpression does not visibly alter prostatic bud formation or branching morphogenesis, and Edar expression is not necessary for either of these events. However, Edar overexpression is associated with an abnormally thick and collagen-rich stroma in adult mouse prostates. These results support CTNNB1 as a transcriptional activator of Edar and Wnt10b in the developing prostate and demonstrate Edar is not only important for ectodermal appendage patterning but also influences collagen organization in adult prostates. This article has an associated First Person interview with the first author of the paper

Effects of Adipose-derived Stromal Cells and of their Extract on Wound Healing in a Mouse Model

In this study, the authors investigated the effects of adipose-derived stromal cells (ADSCs) and of their extract on wound healing. After creating wound healing splint model on the backs of mice, ADSCs and their extract were applied. Wound healing rates were calculated at 3, 5, 7, 10, and 14 days after the wounding, and tissues were harvested at 7 and 14 days for histological analysis. Wound healing rates were significantly higher at 7, 10, and 14 days in the cell group than in the control, but in the cell extract group wound healing rates were significantly decreased (P<0.05). Histological scores and capillary densities in the cell group were significantly higher at 2 weeks (P<0.05). In the cell group, thick inflammatory cell infiltration and many capillaries were observed at 1 week, and thick epithelium and numerous large capillaries were observed at 2 weeks. The present study suggests that ADSCs accelerate wound healing as known, and the effects of ADSCs on wound healing may be due to replacing insufficient cells by differentiation of ADSCs in the wound and secreting growth factors by differentiated cells, and not due to the effect of factors within ADSCs

Connective Tissue Growth Factor Causes Persistent Proα2(I) Collagen Gene Expression Induced by Transforming Growth Factor-β in a Mouse Fibrosis Model

Skin fibrotic disorders such as systemic sclerosis (SSc) are characterized by an excessive production of extracellular matrix (ECM) and understood to develop under the influence of certain growth factors. Connective tissue growth factor (CTGF) is a cysteine-rich mitogenic peptide that is implicated in various fibrotic disorders and induced in fibroblasts after activation with transforming growth factor-beta (TGF-beta). To better understand the mechanisms of persistent fibrosis seen in SSc, we previously established an animal model of skin fibrosis induced by exogenous application of growth factors. In this model, TGF-beta transiently induced subcutaneous fibrosis and serial injections of CTGF after TGF-beta caused persistent fibrosis. To further define the mechanisms of skin fibrosis induced by TGF-beta and CTGF in vivo, we investigated in this study, the effects of growth factors on the promoter activity of the pro alpha 2 (1) collagen (COL1A2) gene in skin fibrosis. For this purpose, we utilized transgenic reporter mice harboring the -17 kb promoter sequence of the mouse COL1A2 linked to either a firefly luciferase gene or a bacterial P-galactosidase gene. Serial injections of CTGF after TGF-beta resulted in a sustained elevation of COL1A2 mRNA expression and promoter activity compared with consecutive injection of TGF-beta alone on day 8. We also demonstrated that the number of fibroblasts with activated COL1A2 transcription was increased by serial injections of CTGF after TGF-beta in comparison with the injection of TGF-beta alone. Furthermore, the serial injections recruited mast cells and macrophages. The number of mast cells reached a maximum on day 4 and remained relatively high up to day 8. In contrast to the kinetics of mast cells, the number of macrophages was increased on day 4 and continued to rise during the subsequent consecutive CTGF injections until day 8. These results suggested that CTGF maintains TGF-beta-induced skin fibrosis by sustaining COL1A2 promoter activation and increasing the number of activated fibroblasts. The infiltrated mast cells and macrophages may also contribute to the maintenance of fibrosis

Aberrant innate immune sensing leads to the rapid progression of idiopathic pulmonary fibrosis

Novel approaches are needed to define subgroups of patients with Idiopathic pulmonary fibrosis (IPF) at risk for acute exacerbations and/or accelerated progression of this generally fatal disease. Progression of disease is an integral component of IPF with a median survival of 3 to 5 years. Conversely, a high degree of variability in disease progression has been reported among series. The characteristics of patients at risk of earlier death predominantly rely on baseline HRCT appearance, but this concept that has been challenged. Disparate physiological approaches have also been taken to identify patients at risk of mortality, with varying results. We hypothesized that the rapid decline in lung function in IPF may be a consequence of an abnormal host response to pathogen-associated molecular patterns (PAMPs), leading to aberrant activation in fibroblasts and fibrosis. Analysis of upper and lower lobe surgical lung biopsies (SLBs) indicated that TLR9, a hypomethylated CpG DNA receptor, is prominently expressed at the transcript and protein level, most notably in biopsies from rapidly progressive IPF patients. Surprisingly, fibroblasts appeared to be a major cellular source of TLR9 expression in IPF biopsies from this group of progressors. Further, CpG DNA promoted profibrotic cytokine and chemokine synthesis in isolated human IPF fibroblasts, most markedly again in cells from patients with the rapidly progressive IPF phenotype, in a TLR9-dependent manner. Finally, CpG DNA exacerbated fibrosis in an in vivo model initiated by the adoptive transfer of primary fibroblasts derived from patients who exhibited rapidly progressing fibrosis. Together, these data suggested that TLR9 activation via hypomethylated DNA might be an important mechanism in promoting fibrosis particularly in patients prone to rapidly progressing IPF

Silencing CD36 gene expression results in the inhibition of latent-TGF-β1 activation and suppression of silica-induced lung fibrosis in the rat

<p>Abstract</p> <p>Background</p> <p>The biologically active form of transforming growth factor-β1 (TGF-β1) plays a key role in the development of lung fibrosis. CD36 is involved in the transformation of latent TGF-β1 (L-TGF-β1) to active TGF-β1. To clarify the role of CD36 in the development of silica-induced lung fibrosis, a rat silicosis model was used to observe both the inhibition of L-TGF-β1 activation and the antifibrotic effect obtained by lentiviral vector silencing of CD36 expression.</p> <p>Methods</p> <p>The rat silicosis model was induced by intratracheal injection of 10 mg silica per rat and CD36 expression was silenced by administration of a lentiviral vector (Lv-shCD36). The inhibition of L-TGF-β1 activation was examined using a CCL-64 mink lung epithelial growth inhibition assay, while determination of hydroxyproline content along with pathological and immunohistochemical examinations were used for observation of the inhibition of silica-induced lung fibrosis.</p> <p>Results</p> <p>The lentiviral vector (Lv-shCD36) silenced expression of CD36 in alveolar macrophages (AMs) obtained from bronchoalveolar lavage fluid (BALF) and the activation of L-TGF-β1 in the BALF was inhibited by Lv-shCD36. The hydroxyproline content of silica+Lv-shCD36 treated groups was significantly lower than in other experimental groups. The degree of fibrosis in the silica+Lv-shCD36-treated groups was less than observed in other experimental groups. The expression of collagen I and III in the silica+Lv-shCD36-treated group was significantly lower than in the other experimental groups.</p> <p>Conclusion</p> <p>These results indicate that silencing expression of CD36 can result in the inhibition of L-TGF-β1 activation in a rat silicosis model, thus further preventing the development of silica-induced lung fibrosis.</p

Antisense oligonucleotide inhibition of Heat Shock Protein (HSP) 47 improves bleomycin-induced pulmonary fibrosis in rats

<p>Abstract</p> <p>Background</p> <p>The most common pathologic form of pulmonary fibrosis arises from excessive deposition of extracellular matrix proteins such as collagen. The 47 kDa heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that has been shown to play a major role during the processing and/or secretion of procollagen.</p> <p>Objectives</p> <p>To determine whether inhibition of HSP47 could have beneficial effects in mitigating bleomycin-induced pulmonary fibrosis in rats.</p> <p>Methods</p> <p>All experiments were performed with 250–300 g male Wistar rats. Animals were randomly divided into five experimental groups that were administered: 1) saline alone, 2) bleomycin alone, 3) antisense HSP47 oligonucleotides alone, 4) bleomycin + antisense HSP47 oligonucleotides, and 5) bleomycin + sense control oligonucleotides. We investigated lung histopathology and performed immunoblot and immunohistochemistry analyses.</p> <p>Results</p> <p>In rats treated with HSP47 antisense oligonucleotides, pulmonary fibrosis was significantly reduced. In addition, treatment with HSP47 antisense oligonucleotides significantly improved bleomycin-induced morphological changes. Treatment with HSP47 antisense oligonucleotides alone did not produce any significant changes to lung morphology. Immunoblot analyses of lung homogenates confirmed the inhibition of HSP47 protein by antisense oligonucleotides. The bleo + sense group, however, did not exhibit any improvement in lung pathology compared to bleomycin alone groups, and also had no effect on HSP47 expression.</p> <p>Conclusion</p> <p>These findings suggest that HSP47 antisense oligonucleotide inhibition of HSP47 improves bleomycin-induced pulmonary fibrosis pathology in rats.</p