Involvement of NK 1.1-positive γδT cells in interleukin-18 plus interleukin-2-induced interstitial lung disease

Interstitial lung disease (ILD) is induced by various factors in humans. However, the exact mechanism of ILD remains elusive. This study sought to determine the role of natural killer (NK) 1.1(+) γδT cells in ILD. The injection of IL-18 plus IL-2 (IL-18/IL-2) into C57BL6 (B6) mice induced acute ILD that resembled early-stage human ILD. An accumulation of NK1.1(+) γδT cells similar to NK cells was evident in the lungs. The T Cell Receptor (TCR) Vγ and Vδ repertoires of NK1.1(+) γδT cells indicated polyclonal expansion. The expression of IL-2 receptor β (Rβ) and IL-18Rβ in NK1.1(+) γδT cells was higher than in NK1.1(-) γδT cells. IL-18/IL-2 stimulated the proliferation of NK1.1(+) γδT cells, but not NK1.1(-) γδT cells. The IL-18/IL-2-stimulated NK1.1(+) γδT cells produced higher concentrations of IFN-γ than did NK1.1(-) γδT cells. Moreover, NK1.1(+) γδT and NK1.1(-) γδT cells constituted completely different cell populations. The IL-18/IL-2-induced ILD was milder in TCRδ(-/-) and IFN-γ(-/-) mice, compared with B6 mice. Furthermore, cell-transfer experiments demonstrated that NK1.1(+) γδT cells could induce the expansion of NK cells and IFN-γ mRNA in the lung by IL-18/IL-2. Our results suggest that NK1.1(+) γδT cells function as inflammatory mediators in the early phase of IL-18/IL-2-induced ILD.     

Inhibition of Mycobacterium tuberculosis-induced signalling by transforming growth factor-β in human mononuclear phagocytes

Tuberculosis (TB) is associated with excessive production and bioactivation of transforming growth factor bets (TGF-β) in situ. Here, modification of expression of components of plasminogen/plasmin pathway in human monocytes (MN) by inhibitors of TGF-β signalling was examined. Smad3 siRNA effectively inhibited TGF-β-induced urokinase plasminogen activator receptor (uPAR). Agents known to interfere with TGF-β signalling, including the Smad inhibitors SIS3 and erythromycin derivatives, and ALK5 receptor inhibitor (SB 431542) in inhibition of uPAR expression in response to Mycobacterium tuberculosis (MTB) were examined. Inhibition by SIS3 only inhibited uPAR mRNA significantly. SIS3 may prove to be an effective adjunct to TB therapy.     

Roles of transforming growth factor-α in mammary development and disease

Transforming growth factor-alpha (TGFα) is a member of the epidermal growth factor (EGF) family. Expression of TGFα is highly regulated in response to exogenous cellular signals including cytokines and other growth factors. The growth factor has been found to be indispensable for proper development of many tissues and organs. TGFα has also been implicated in numerous disease states including forms of breast cancer. This minireview summarizes the basic biology of TGFα and its actions during normal and pathogenic development of the mammary epithelium.     

The effects of triptolide on airway remodelling and transforming growth factor-β₁/Smad signalling pathway in ovalbumin-sensitized mice

Airway remodelling contributes to increased morbidity and mortality in asthma. We have reported that triptolide, the major component responsible for the immunosuppressive and anti‐inflammatory effects of Tripterygium wilfordii Hook F, inhibited pulmonary inflammation in patients with steroid‐resistant asthma. In the present study, we investigated whether triptolide inhibits airway remodelling in a mouse asthma model and observed the effects of triptolide on the transforming growth factor‐β₁ (TGF‐β₁)/Smad pathway in ovalbumin (OVA) ‐sensitized mice. BALB/c mice were sensitized to intraperitoneal OVA followed by repetitive OVA challenge for 8 weeks. Treatments included triptolide (40 μg/kg) and dexamethasone (2 mg/kg). The area of bronchial airway (WAt/basement membrane perimeter) and smooth muscle (WAm/basement membrane perimeter), mucus index and collagen area were assessed 24 hr after the final OVA challenge. Levels of TGF‐β₁ were assessed by immunohistology and ELISA, levels of TGF‐β₁ mRNA were measured by RT‐PCR, and levels of pSmad2/3 and Smad7 were assessed by Western blot. Triptolide and dexamethasone significantly reduced allergen‐induced increases in the thickness of bronchial airway and smooth muscle, mucous gland hypertrophy, goblet cell hyperplasia and collagen deposition. Levels of lung TGF‐β₁, TGF‐β₁ mRNA and pSmad2/3 were significantly reduced in mice treated with triptolide and dexamethasone, and this was associated with a significant increase in levels of Smad7. Triptolide may function as an inhibitor of asthma airway remodelling. It may be a potential drug for the treatment of patients with a severe asthma airway.     

Fibroblast growth factor-2 promotes in vitro mitral valve interstitial cell repair through transforming growth factor-β/Smad signaling

Transforming growth factor (TGF)-β and fibroblast growth factor (FGF)-2 both promote repair in valve interstitial cell (VIC) injury models; however, the relationship between TGF-β and FGF-2 in wound repair are not well understood. VIC confluent monolayers were wounded by mechanical injury and incubated separately or in combination with FGF-2, neutralizing antibody to FGF-2, neutralizing antibody to TGF-β, and betaglycan antibody for 24 hours after wounding. Phosphorylated Smad2/3 (pSmad2/3) was localized at the wound edge (WE) and at the monolayer away from the WE. Down-regulation of pSmad2/3 protein expression via small-interfering RNA transfection was performed. The extent of wound closure was monitored for up to 96 hours. FGF-2 incubation resulted in a significant increase in nuclear pSmad2/3 staining at the WE. Neutralizing antibody to TGF-β alone or with FGF-2 present resulted in a similar significant decrease in pSmad2/3. Neutralizing antibody to FGF-2 alone or with FGF-2 present showed a similar significant decrease in pSmad2/3; however, significantly more staining was observed than treatment with neutralizing antibody to TGF-β. Incubation with betaglycan antibody inhibited FGF-2-mediated pSmad2/3 signaling. Wound closure corresponded with pSmad2/3 staining at the WE. Down-regulation of pSmad2/3 via small-interfering RNA transfection significantly reduced the extent to which FGF-2 promoted wound closure. Fibroblast growth factor-2 promotes in vitro VIC wound repair, at least in part, through the TGF-β/Smad2/3 signaling pathway.     

Decreased production of interleukin-10 and transforming growth factor-�� in Toll-like receptor-activated intestinal B cells in SAMP1/Yit mice

A unique subset of B cells expressing interleukin‐10 (IL‐10) and transforming growth factor‐β (TGF‐β) plays an essential role in preventing inflammation and autoimmunity. We investigated the presence of this cell subset in intestines and its role in the pathogenesis of ileitis using SAMP1/Yit and age‐matched control AKR/J mice. Mononuclear cells were isolated from mesenteric lymph nodes (MLNs) and the expressions of B220, CD1d, CD5, Toll‐like receptor 4 (TLR4) and TLR9 in isolated cells were analysed. Purified B cells were stimulated with lipopolysaccharide (LPS) or CpG‐DNA, then IL‐10 and TGF‐β₁ expressions were examined by enzyme immunoassay and flow cytometry. Production of IL‐1β by TLR‐mediated macrophages co‐cultured with or without purified MLN B cells from SAMP1/Yit and AKR/J mice was evaluated. In addition, interferon‐γ (IFN‐γ) production in intestinal T cells co‐cultured with MLN B cells were also assessed in SAMP1/Yit and AKR/J strains. The production levels of IL‐10 and TGF‐β₁ stimulated by LPS and CpG‐DNA were significantly lower in B cells separated from MLNs from the SAMP1/Yit strain. B cells expressing IL‐10 and TGF‐β₁ were mainly located in a population characterized by the cell surface marker CD1d⁺. Interleukin‐1β production by TLR‐activated macrophages co‐cultured with MLN B cells from SAMP1/Yit mice was significantly higher than that of those from AKR/J mice. Interestingly, IFN‐γ production by T cells was noted only when they were co‐cultured with SAMP1/Yit but not the AKR/J B cells. These results are the first to show that disorders of regulatory B‐cell function under innate immune activation may cause disease pathogenesis in a murine model of Crohn’s disease.     

Inhibition airway remodeling and transforming growth factor-β1/Smad signaling pathway by astragalus extract in asthmatic mice

Airway remodeling is characterized by airway wall thickening, subepithelial ?brosis, increased smooth muscle mass, angiogenesis and increased mucous glands, which can lead to a chronic and obstinate asthma with pulmonary function depression. In the present study, we investigated whether the astragalus extract inhibits airway remodeling in a mouse asthma model and observed the effects of astragalus extract on the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway in ovalbumin-sensitized mice. Mice were sensitized and challenged by ovalbumin to establish a model of asthma. Treatments included the astragalus extract and budesonide. Lung tissues were obtained for hematoxylin and eosin staining and Periodic acid-Schiff staining after the ?nal ovalbumin challenge. Levels of TGF-β1 were assessed by immunohistology and ELISA, levels of TGF-β1 mRNA were measured by RT-PCR, and levels of P-Smad2/3 and T-Smad2/3 were assessed by western blotting. Astragalus extract and budesonide reduced allergen-induced increases in the thickness of bronchial airway and mucous gland hypertrophy, goblet cell hyperplasia and collagen deposition. Levels of lung TGF-β1, TGF-β1 mRNA and P-Smad2/3 were signi?cantly reduced in mice treated with astragalus extract and budesonide. Astragalus extract improved asthma airway remodeling by inhibiting the expression of the TGF-β1/Smad signaling pathway, and may be a potential drug for the treatment of patients with a severe asthma airway.     

Retinoic acid induced repair in the lung of adult hyperoxic mice,reducing transforming growth factor-β1 (TGF-β1) mediated abnormal alterations

The aim of the study was to determine the effects of retinoic acid on lung alveolar repair in adult hyperoxic mice and to investigate the relationship between TGF-β1 and retinoic acid during the repair processes. Adult mice were divided into 4 groups. Two groups were given daily intraperitoneal injections of peanut oil/dimethylsulfoxide mixture and retinoic acid (50 mg/kg body weight, 50 μl of volume) dissolved in peanut oil/dimethylsulfoxide mixture for 12 days with a 2-day break on days 6 and 7. Following hyperoxia (100% oxygen) for 72 h the remaining two groups were treated in the same manner as already described: peanut oil/dimethylsulfoxide mixture and retinoic acid. Lung structure was investigated by light microscopy. TGF-β1 and Smad protein expressions in the lung were assayed by biochemical methods. Hyperoxic mice exhibited damage to the alveolar walls, increased cell proliferation and induced Smad3/TGF-β1 signaling. Smad2 and phospho-Smad2 protein expressions were unchanged in all groups. Retinoic acid administration improved the degenerative alterations caused by hyperoxia and helped in alveolar repair. This positive effect of retinoic acid resulted from the inhibition of Smad3/TGF-β1 signaling via reduced Smad4 mRNA and increased Smad7 protein expression. Retinoic acid also induced alveolarization and restricted Smad3/TGF-β1 signaling by decreasing Smad4 mRNA in healthy mice. Thus, retinoic acid helped repair Smad3/TGF-β1-induced lung damage in hyperoxic mice.     

Inhibition of transforming growth factor β worsens elastin degradation in a murine model of Kawasaki disease

Kawasaki disease (KD) is an acute inflammatory illness marked by coronary arteritis. However, the factors increasing susceptibility to coronary artery lesions are unknown. Because transforming growth factor (TGF) β increases elastin synthesis and suppresses proteolysis, we hypothesized that, in contrast to the benefit observed in aneurysms forming in those with Marfan syndrome, inhibition of TGF-β would worsen inflammatory-induced coronary artery lesions. By using a murine model of KD in which injection of Lactobacillus casei wall extract (LCWE) induces coronary arteritis, we show that LCWE increased TGF-β signaling in the coronary smooth muscle cells beginning at 2 days and continuing through 14 days, the point of peak coronary inflammation. By 42 days, LCWE caused fragmentation of the internal and external elastic lamina. Blocking TGF-β by administration of a neutralizing antibody accentuated the LCWE-mediated fragmentation of elastin and induced an overall loss of medial elastin without increasing the inflammatory response. We attributed these increased pathological characteristics to a reduction in the proteolytic inhibitor, plasminogen activator inhibitor-1, and an associated threefold increase in matrix metalloproteinase 9 activity compared with LCWE alone. Therefore, our data demonstrate that in the coronary arteritis associated with KD, TGF-β suppresses elastin degradation by inhibiting plasmin-mediated matrix metalloproteinase 9 activation. Thus, strategies to block TGF-β, used in those with Marfan syndrome, are unlikely to be beneficial and could be detrimental.     

Polymorphisms of transforming growth factor-β signaling pathway and Kawasaki disease in the Taiwanese population

Kawasaki disease (KD) is a systemic vasculitis associated with cardiovascular symptom. A previous study in the European descent has indicated that genetic variants of the transforming growth factor-β (TGF-β) pathway are involved in the KD susceptibility and clinical status. This study was conducted to investigate if polymorphisms in TGF-β signaling pathway are associated with KD susceptibility, and the coronary artery lesion formation. A total of 950 subjects (381 KD patients and 569 controls) were investigated to identify 12 single-nucleotide polymorphisms in the TGF-β signaling pathway (rs2796817, rs10482751, rs2027567, rs12029576, rs11466480, rs4776338, rs12901071, rs7162912, rs1438386, rs6494633, rs12910698 and rs4776339) by using TaqMan Allelic Discrimination assay. Our results indicated that rs1438386 in the SMAD3 is significantly associated with the susceptibility of KD. Additionally, both haplotypes of TGFβ2 and SMAD3 were also associated with the risk of KD. This study showed that genetic polymorphisms in TGF-β signaling pathway are associated with KD susceptibility, but not coronary artery lesions formation, or intravenous immunoglobulin treatment response in the Taiwanese population.     

Effects of interleukin-6 (IL-6) and transforming growth factor-β (TGF-β) on neutrophil elastase release

The proinflammatory cytokine interleukin-6 (IL-6) and its potential opponent, transforming growth factor- (TGF- ₁), have been discussed as being involved in the regulation of inflammatory processes following trauma and infections. The aim of this study was to investigate the effect of these cytokines on the regulation of neutrophil degranulation. The posttraumatic time courses of the plasma concentrations of IL-6, and the elastase- ₁-proteinase-inhibitor complex as marker of degranulation in patients undergoing severe trauma were found to be highly correlated, whereas TGF- ₁ levels were determined to be not significantly altered. The close temporal correlation of IL-6 and elastase levels could be confirmed by investigation of exudates derived from the surgical area. To prove these in vivo findings, the effect of IL-6 and TGF- ₁ on the degranulation of isolated neutrophils of healthy donors was investigated in vitro. Pathological high IL-6 concentrations were found to be capable of inducing a significant release of lysosomal elastase in a concentration-dependent manner, whereas the degranulation was unaffected by TGF- ₁. In conclusion, these data suggest an involvement of IL-6 in the regulation of neutrophil degranulation under pathological conditions. However, TGF- ₁ seems to have no direct regulatory effect besides its described chemotactic function on neutrophils.     

Dynamic expression patterns of transforming growth factor-β<Subscript>2</Subscript> and transforming growth factor-β receptors in experimental glomerulonephritis

Numerous studies have demonstrated the involvement of the transforming growth factor (TGF) isoform beta(1) in the pathogenesis of renal fibroproliferative diseases. Although in vitro studies suggest that TGF-beta(2) is equally potent to TGF-beta(1) in terms of its antimitogenic and fibrogenic effects, much less is known about the regulation of TGF-beta(2) in renal diseases associated with glomerular cell hyperplasia and matrix expansion. Here we investigated the glomerular expression patterns of TGF-beta(2) and of the TGF-beta receptors I, II, and III during the course of rat anti-Thy1.1 nephritis (days 2, 6, 12, and 56), a model characterized by transient mesangial hypercellularity and extracellular matrix accumulation. TGF-beta(2) exhibited dynamic changes in expression. Immunohistochemical double-staining of renal sections revealed that most TGF-beta(2)-positive cells in control glomeruli were podocytes with few TGF-beta(2)-positive mesangial cells. This staining pattern could also be observed in human kidney. On day 6 of anti-Thy1.1 nephritis both TGF-beta(2) positive podocytes and mesangial cells were more abundant. By western blot analysis of isolated glomeruli from nephritic rats, protein expression of TGF-beta(2) was upregulated tenfold over control glomeruli, peaking on day 6 of the disease. In cultured rat mesangial cells we found that the TGF-beta(2) and TGF-beta(1) isoforms were equally potent in terms of nuclear accumulation of phosphorylated Smad 2/3, inhibition of DNA synthesis, and induction of beta(1)-integrin and type I collagen protein synthesis. Protein expression of the TGF-beta receptor I was not detected by immunohistochemistry in control glomeruli but was markedly induced in the mesangium on day 6 of nephritis. Mesangial staining for TGF-beta receptors II and III was detected in normal kidneys. Expression of TGF-beta receptor II was strongly enhanced on days 6 and 12 of disease, while TGF-beta receptor III was upregulated only on day 6. In summary, we report marked yet transient upregulation of TGF-beta(2) protein and of TGF-beta receptors I, II, and III in glomerular cells during anti-Thy1.1 nephritis. These results are in keeping with the notion that TGF-beta(2) and its receptors participate in the pathogenesis and/or resolution of this transient form of glomerulonephritis.     

Transforming growth factor-β (TGFβ) inhibition of epstein-barr virus (EBV)- and interleukin-4 (IL-4)-induced immunoglobulin production in human B lymphocytes

This study reports on the effects of TGF on the secretion of Ig isotypes by highly purified (>99% CD20-positive) human peripheral blood B cells. Stimulation of these B cell preparations with EBV resulted in the secretion of IgM, IgG, and IgA and the addition of IL-4 induced readily detectable levels (>100 ng/ml) of IgE between 10 and 25 days of culture. TGF1 and TGF2 showed similar dose-dependent suppression of IgM, IgG, and IgA, and the relative proportion of IgG and IgA remained unchanged in the presence of TGF. IgE production induced by EBV and IL-4 was significantly inhibited by TGF. TGF effects on Ig secretion were not related to inhibition of B cell proliferation by this cytokine. In contrast to these TGF effects on EBV activation of primary B cells, the constitutive Ig secretion by EBV-transformed B cells was resistant to TGF, while the increase in Ig secretion induced by IL-6 was inhibited by TGF. Thus, TGF inhibits the EBV-induced secretion of the major Ig isotypes in peripheral blood B cells and has differential effects on Ig secretion by transformed B cells.     

Aberrant expression of cytokine interleukin 9 along with interleukin 4 and interferon γ in connective tissue disease-associated interstitial lung disease: association with severity of pulmonary fibrosis

Introduction

Connective tissues diseases (CTDs) are a heterogeneous group of disorders that share certain clinical characteristics and disturbed immunoregulation. Interstitial lung diseases (ILDs), also known as diffuse parenchymal lung diseases, are among the most serious pulmonary complications associated with CTDs. Interleukin 9 (IL-9), IL-4 and interferon γ (IFN-γ) – cytokines with important roles in autoimmune disease – were studied in CTD patients and CTD-ILD patients.

Material and methods

Sixty-one hospitalized untreated CTD patients were recruited, and 20 healthy volunteers were enrolled as controls. The 61 CTD patients were divided into a simple CTD group and a CTD-ILD group, and the plasma protein IL-9, IL-4 and IFN-γ levels were measured by enzyme-linked immunosorbent assay (ELISA).

Results

The results indicate that the serum IL-9 levels were significantly higher in CTD-ILD and simple CTD patients than they were in healthy controls (each p < 0.05) and that the levels were elevated in CTD-ILD patients compared with simple CTD patients (p < 0.05). The IL-4 levels were higher in CTD-ILD patients than they were in the simple CTD patients (p < 0.05) and healthy controls (p < 0.01). In addition, the serum IL-9 levels were negatively correlated with the level of IFN-γ (r² = 0.34, p = 0.01), the estimated percentage of predicted forced vital capacity (FVC%) (r² = 0.36, p = 0.00) and the estimated percentage of predicted diffusing capacity (DLCO%) (r² = 0.27, p = 0.04) and were positively correlated with the IL-4 level (r² = 0.31, p = 0.01).

Conclusions

Interleukin-9 may play an important role in the pathogenesis of CTD and may contribute to the progression of interstitial lung injury in CTD patients.     

Exercise-induced changes in circulating levels of transforming growth factor-β-1 in humans: methodological considerations

Mechanical loading of cells induces the expression of transforming growth factor-beta-1, and acute exercise, which involves mechanical loading of several tissues, could thus increase its circulating level in humans. However, no consensus exists regarding the plasma concentration of this cytokine in resting subjects (reported values range from 500 to 18,300 pg ml(-1)) and also the extent of intra-individual variation is unknown. As a basis for detecting exercise-induced changes in transforming growth factor-beta-1, we measured its concentration, by enzyme-linked immunosorbent assay, in plasma from eight healthy resting subjects. Plasma was sampled from each subject on five successive days according to a procedure designed to minimize activation of platelets, as platelet alpha-granules contain large amounts of transforming growth factor-beta-1. The mean plasma level was relatively low [1155 (30) pg ml(-1), mean (SE)], and did not differ between days, indicating that platelet activation was minimal. Several alterations in the blood sampling procedure did not affect results, while a 40% increase was seen when blood was not cooled appropriately prior to centrifugation. A moderate intra-individual variation (average CV=9.8%) indicated a stable plasma level at rest. In response to exercise (1 h of treadmill running) the plasma concentration of transforming growth factor-beta-1 increased from 992 (49) pg ml(-1) (at rest) to 1301 (39) pg ml(-1) (post exercise) ( P<0.05) ( n=6). In conclusion, the resting plasma level of transforming growth factor-beta-1 was stable over time when blood samples were treated appropriately. Exercise increased the plasma concentration, perhaps indicating a release from mechanically loaded tissues.     

Effect of PKC signalling pathway and aldose reductase on expression of fibronectin induced by transforming growth factor-β1 in human mesangial cells

Objective To study the effect of PKC signalling pathway and aldose reductase (AR) on the expression of fibronectin (FN) induced by transforming growth factor-β1 (TGF-β1). Methods Human mesangial cells (HMCs) were cultured and transfected with pcDNA3-AR, and subject to AR gene silencing with small interfering RNA (siRNA) and then the cell was treated with recombinant human TGF-β1. The AR mRNA expression in the HMCs was examined using real time RT-PCR and protein expression of AR and FN was detected by Western blotting. Results The cultured HMC treated with TGF-$l showed increased expression of AR and FN,the normal HMC showed not reduced expression of FN after incubation with single inhibitors of AR. Pre-incubation of cells with inhibitors of AR and PKC, then the different groups of cells were treated with TGF-$l ,and the induction effect on FN expression was suppressed (34%) in HMC. HMCs transfected with AR showed a strong protein expression of FN, which was increased by 3. 6-fold after treatment with TGF-pl (P <0. 05) , and the induction effect on FN expression was suppressed by G(O)6983 (42%) in HMCs (P < 0. 05) . The HMC with AR gene knock-down by siRNA showed a decreased expression of AR and 90% decrease of FN protein in HMCs(P <0. 01) , and TGF-β1-induced up-regulation of FN was significantly suppressed by siRNA (12%) in HMCs (P <0. 01). Conclusions AR is capable of regulating FN expression only in the presence of TGF-β1, and this reaction is possibly accomplished through the activation of PKC signalling pathway.     

Effect of PKC signalling pathway and aldose reductase on expression of fibronectin induced by transforming growth factor-β1 in human mesangial cells

Objective To study the effect of PKC signalling pathway and aldose reductase (AR) on the expression of fibronectin (FN) induced by transforming growth factor-β1 (TGF-β1). Methods Human mesangial cells (HMCs) were cultured and transfected with pcDNA3-AR, and subject to AR gene silencing with small interfering RNA (siRNA) and then the cell was treated with recombinant human TGF-β1. The AR mRNA expression in the HMCs was examined using real time RT-PCR and protein expression of AR and FN was detected by Western blotting. Results The cultured HMC treated with TGF-$l showed increased expression of AR and FN,the normal HMC showed not reduced expression of FN after incubation with single inhibitors of AR. Pre-incubation of cells with inhibitors of AR and PKC, then the different groups of cells were treated with TGF-$l ,and the induction effect on FN expression was suppressed (34%) in HMC. HMCs transfected with AR showed a strong protein expression of FN, which was increased by 3. 6-fold after treatment with TGF-pl (P <0. 05) , and the induction effect on FN expression was suppressed by G(O)6983 (42%) in HMCs (P < 0. 05) . The HMC with AR gene knock-down by siRNA showed a decreased expression of AR and 90% decrease of FN protein in HMCs(P <0. 01) , and TGF-β1-induced up-regulation of FN was significantly suppressed by siRNA (12%) in HMCs (P <0. 01). Conclusions AR is capable of regulating FN expression only in the presence of TGF-β1, and this reaction is possibly accomplished through the activation of PKC signalling pathway.     

Severe gammaherpesvirus-induced pneumonitis and fibrosis in syngeneic bone marrow transplant mice is related to effects of transforming growth factor-β

Pulmonary infections and pneumonitis occur frequently after hematopoietic stem cell transplantation. Using a syngeneic mouse model of bone marrow transplantation (BMT), we have previously demonstrated that BMT mice are more susceptible to acute gammaherpesvirus 68 (MHV-68) replication at day 7 after infection. By day 21, the virus is latent in lungs of BMT and control mice, and there is no difference in viral load. Despite similar latent viral load, BMT mice develop severe pneumonitis associated with reduced oxygen saturation, fibrosis, peripheral inflammation, hyaline membranes, and foamy alveolar macrophages, a phenotype that persists for 7 weeks after infection. BMT mice demonstrate increased bronchoalveolar lavage (BAL) cells, and this population is enriched in neutrophils and T cells. Alternatively, activated macrophages appear earlier than do classically activated macrophages. BAL fluid from BMT mice at day 21 after infection contains increased levels of hydrogen peroxide, nitrite, and transforming growth factor-β (TGF-β). Mice expressing the dominant-negative transgene dn-TGFβRII in multiple cell types were used as BMT donors. BMT mice with T-cell dnTGFβRII are largely protected from the pneumonitis phenotype, whereas mice with CD11c-dnTGFβRII BMT mice are only modestly protected from pneumonitis. Protection in BMT mice with T-cell dnTGFβRII is associated with decreased TGF-β derived from parenchymal cells in the BAL fluid, lower nitrite levels, and reduced apoptosis, whereas alternatively activated macrophage markers are unchanged.