Hydrogen sulfide suppresses transforming growth factor-β1-induced differentiation of human cardiac fibroblasts into myofibroblasts

In heart disease, transforming growth factor-β1(TGF-β1) converts fibroblasts into myofibroblasts, which synthesize and secrete fibrillar type I and III collagens. The purpose of the present study was to investigate how hydrogen sulfide(H2S) suppresses TGF-β1-induced differentiation of human cardiac fibroblasts to myofibroblasts. Human cardiac fibroblasts were serum-starved in fibroblast medium for 16 h before exposure to TGF-β1(10 ng m L-1) for 24 h with or without sodium hydrosulfide(Na HS, 100 μmol L-1, 30 min pretreatment) treatment. Na HS, an exogenous H2 S donor, potently inhibited the proliferation and migration of TGF-β1-induced human cardiac fibroblasts and regulated their cell cycle progression. Furthermore, Na HS treatment led to suppression of fibroblast differentiation into myofibroblasts, and reduced the levels of collagen, TGF-β1, and activated Smad3 in TGF-β1-induced human cardiac fibroblasts in vitro. We therefore conclude that H2 S suppresses TGF-β1-stimulated conversion of fibroblasts to myofibroblasts by inhibiting the TGF-β1/Smad3 signaling pathway, as well as by inhibiting the proliferation, migration, and cell cycle progression of human cardiac myofibroblasts. These effects of H2 S may play significant roles in cardiac remodeling associated with heart failure.     

Mechanisms of the alternative activation of macrophages and non-coding RNAs in the development of radiation-induced lung fibrosis

Radiation-induced lung fibrosis(RILF) is a common side effect of thoracic irradiation therapy and leads to high mortality rates after cancer treatment. Radiation injury induces inflammatory M1 macrophage polarization leading to radiation pneumonitis, the first stage of RILF progression. Fibrosis occurs due to the transition of M1 macrophages to the anti-inflammatory pro-fibrotic M2 phenotype, and the resulting imbalance of macrophage regulated inflammatory signaling. Non-coding RNA signaling has been shown to play a large role in the regulation of the M2 mediated signaling pathways that are associated with the development and progression of fibrosis. While many studies show the link between M2 macrophages and fibrosis, there are only a few that explore their distinct role and the regulation of their signaling by non-coding RNA in RILF. In this review we summarize the current body of knowledge describing the roles of M2 macrophages in RILF, with an emphasis on the expression and functions of non-coding RNAs.     

Cortactin is involved in transforming growth factor-β1-induced epithelial-mesenchymal transition in AML-12 cells

Cortactin is an F-actin binding protein, regulating cell movement and adhesive junction assembly. However, the function of cortactin in epithelial-mesenchymal transition （EMT） remains elusive. Here we found that during transforming growth factor-β1 （TGF-β1）- induced EMT in AML-12 murine hepatocytes, cortactin underwent tyrosine dephosphorylation. Inhibition of the dephosphorylation of eortactin by sodium vanadate blocked TGF-β1-induced EMT. Knockdown of cortactin by RNAi led to decrease of intercellular junction proteins E-cadherin and Zonula occludens-1 and induced expression of mesenchymal protein fibronectin. Additionally, knockdown of cortactin further promoted TGF-β1-induced EMT in AML-12 cells, as determined by EMT markers and cell morphological changes. Moreover, migration assay showed that cortactin knockdown promoted the migration of AML-12 cells, and also enhanced TGF-β1-induced migration. Our study showed the involvement of cortactin in the TGF- β1-induced EMT.     

A novel reporter mouse line for studying alveolar macrophages

Alveolar macrophages(AMs) are self-maintained immune cells that play vital roles in lung homeostasis and immunity. Although reporter mice and culture systems have been established for studying macrophages, an accurate and specific reporter line for alveolar macrophage study is still not available. Here we reported a novel Rspo1-td Tomato gene reporter mouse line that could specifically label mouse AMs in a cell-intrinsic manner. Using this reporter system, we visualized the dynamics of alveolar ...     

Adhesion, orientation, and movement of cells cultured on ultrathin fibronectin fibers

Summary This study examined the behavior of rat tendon fibroblasts, baby hamster kidney fibroblasts, macrophage-like P388D1 cells, and neurons from rat dorsal root ganglia, cultured on fibronectin strands 0.2–5 μm in diameter. We investigated cell spreading, orientation, formation of focal contacts, the speed of cell movement, and the speed of neurite outgrowth in cells cultured on fibronectin strands, glass covered with fibronectin, and plain, nontreated glass. Fibronectin strands significantly promoted cell spreading and caused a marked alignment of all kinds of cells to the direction of the fiber. The fibers caused the alignment of actin filaments in fibroblasts and focal contacts in fibroblasts and macrophages and increased polymerization of F-actin in cells. Fibronectin fibers also increased the speed and persistence of cell movement and the rate of neurite outgrowth. Macrophages grown on fibronectin fibers produced numerous actin-rich microspikes and adopted a polarized, migratory phenotype. These findings indicate that fibronectin strands, resembling natural components of the extracellular matrix, are more effective in activating various types of cells than two-dimensional, fibronectin-covered substrata. The results also confirm the suitability of the three-dimensionally oriented fibronectin form for use in clinical practice.     

LncRNA CFAR promotes cardiac fibrosis via the miR-449a-5p/LOXL3/mTOR axis

Cardiac fibrosis is one of the crucial pathological factors in the heart, and various cardiac conditions associated with excessive fibrosis can eventually lead to heart failure. However, the exact molecular mechanism of cardiac fibrosis remains unclear. In the present study, we show that a novel lnc RNA that we named cardiac fibrosis-associated regulator(CFAR) is a profibrotic factor in the heart. CFAR was upregulated in cardiac fibrosis and its knockdown attenuated the expression of fibrotic ma...     

Macropinocytosis contributes to the macrophage foam cell formation in RAW264.7 cells

The key event in the atherosclerosis development is the lipids uptake by macrophage and the formation of foam cell in subendothelial arterial space. Besides the uptake of modified low-density lipoprotein （LDL） by scavenger receptor-mediated endocytosis, macrophages possess constitutive macropinocytosis, which is capable of taking up a large quantity of solute. Macrophage foam cell formation could be induced in RAW264.7 cells by increasing the serum concentration in the culture medium. Foam cell formation induced by serum could be blocked by phosphoinositide 3-kinase inhibitor, LY294002 or wortmannin, which inhibited macropinocytosis but not receptor-mediated endocytosis. Further analysis indicated that macropinocytosis took place at the gangliosides-enriched membrane area. Cholesterol depletion by β-methylcyclodextrin-blocked macropinocytosis without affecting scavenger receptormediated endocytosis of modified LDLs. These results suggested that macropinocytosis might be one of the important mechanisms for lipid uptake in macrophage. And it made significant contribution to the lipid accumulation and foam cell formation.     

TGF-β1-promoted epithelial-to-mesenchymal transfor mation and cell adhesion contribute to TGF-β1-enhanced cell migration in SMMC-7721 cells

Transforming growth factor-bl (TGF-β1), a multi-function polypeptide, is a double-edged sword in cancer. For some tumor cells, TGF-β1 is a potent growth inhibitor and apoptosis inducer. More commonly, TGF-β1 losesits growth-inhibitory and apoptosis-inducing effects, but stimulates the metastatic capacity of tumor cells. It is currently little known about TGF-β1-promoted cell migration in hepatocellular carcinoma (HCC) cells, let alone its mechanism. In this study, we found that TGF-β1 lost its tumor-suppressive effects, but significantly stimulated cellmigration in SMMC-7721 human HCC cells. By FACS and Western blot analysis, we observed that TGF-β1 enhanced the expression of ct5131 integrin obviously, and subsequently stimulated cell adhesion onto fibronectin(Fn). Furthermore, we observed that TGF-β1 could also promote SMMC-7721 cells adhesion onto laminin (Ln).Our data also provided evidences that TGF-β1 induced epithelial-to-mesenchymal transformation (EMT) in SMMC-7721 cells. First, SMMC-7721 cells clearly switched to the spindle shape morphology after TGF-β1 treatment.Furthermore, TGF-β1 induced the down-regulation of E-cadherin and the nuclear translocation of β1-catenin. These results indicated that TGF-β1-promoted cell adhesion and TGF-β1-induced epithelial-to-mesenchymal transfor-mation might be both responsible for TGF-β1-enhanced cell migration.     

miRNA-711-SP1-collagen-I pathway is involved in the anti-fibrotic effect of pioglitazone in myocardial infarction

Although microRNAs(miRNAs) have been intensively studied in cardiac fibrosis,their roles in drug-mediated anti-fibrotic therapy are still unknown.Previously,Pioglitazone attenuated cardiac fibrosis and increased miR-711 experimentally.We aimed to explore the role and mechanism of miR-711 in pioglitazone-treated myocardial infarction in rats.Our results showed that pioglitazone significantly reduced collagen-I levels and increased miR-711 expression in myocardial infarction heart.Pioglitazone increased the expression of miR-711 in cardiac fibroblasts,and overexpression of miR-711 suppressed collagen-I levels in angiotensin II(Ang II)-treated or untreated cells.Transfection with antagomir-711 correspondingly abolished the pioglitazone-induced reduction in collagen-I levels.Bioinformatics analysis identified SP1,which directly promotes collagen-I synthesis,as the putative target of miR-711.This was confirmed by luciferase assay and western blot analysis.Additionally,increased SP1 expression was attenuated by pioglitazone in myocardial infarction heart.Furthermore,transfection of antagomir-711 attenuated pioglitazone-reduced SP1 expression in cardiac fibroblasts with or without Ang II stimulation.We conclude that pioglitazone up-regulated miR-711 to reduce collagen-I levels in rats with myocardial infarction.The miR-711-SP1-collagen-I pathway may be involved in the anti-fibrotic effects of pioglitazone.Our findings may provide new strategies for miRNA-based anti-fibrotic drug research.     

Local administration of liposomal-based Plekhf1 gene therapy attenuates pulmonary fibrosis by modulating macrophage polarization

Idiopathic pulmonary fibrosis(IPF) is a fatal interstitial lung disease with limited therapeutic options. Macrophages, particularly alternatively activated macrophages(M2), have been recognized to contribute to the pathogenesis of pulmonary fibrosis.Therefore, targeting macrophages might be a viable therapeutic strategy for IPF. Herein, we report a potential nanomedicinebased gene therapy for IPF by modulating macrophage M2 activation. In this study, we illustrated that the levels of pleckstrin ...     

Phenylalanine diminishes M1 macrophage inflammation

Emerging evidence suggests that amino acids dictate the effector functions of immune cells; however, whether and how phenylalanine(Phe) orchestrates the polarization of macrophages is not understood. Here, we determined that Phe attenuated lipopolysaccharide(LPS) and P. multocida serotype A strain CQ2(PmCQ2) infection-induced inflammation in vivo. Furthermore, we demonstrated that Phe inhibited the production of interleukin(IL)-1β and tumor necrosis factor(TNF)-α in proinflammatory(M1) macrophag...     

Lysyl oxidase promotes bleomycin-induced lung fibrosis through modulating inflammation

Enzymes involved in collagen biosynthesis, including lysyl oxidase （LOX）, have been proposed as potential therapeutic targets for idio- pathic pulmonary fibrosis. LOX expression is significantly upregulated in bleomycin （BLM）-induced lung fibrosis, and knockdown of LOX expression or inhibition of LOX activity alleviates the lung fibrosis. Unexpectedly, treatment of the mice with LOX inhibitor at the inflammatory stage, but not the fibrogenic stage, efficiently reduces collagen deposition and normalizes lung architecture. Inhibition of LOX impairs inflammatory ceU infiltration, TGF-β signaling, and myofibroblast accumulation. Furthermore, ectopic expres- sion of LOX sensitizes the fibrosis-resistant Balb/c mice to BLM-induced inflammation and lung fibrosis. These results suggest that LOX is indispensable for the progression of BLM-induced experimental lung fibrosis by aggravating the inflammatory response and subse- quent fibrosis process after lung injury.     

Emerging roles of transforming growth factor β signaling in wet age-related macular degeneration

Age-related macular degeneration (AMD) is one of the major causes of irreversible blindness among aging populations in developed countries and can be classified as dry or wet according to its progression.Wet AMD,which is characterized by angiogenesis on the choroidal membrane,is uncommonly seen but more severe.Controlling or completely inhibiting the factors that contribute to the progression of events that lead to angiogenesis may be an effective strategy for treating wet AMD.Emerging evidence has shown that transforming growth factor-β(TGF-β) signaling plays a significant role in the progression of wet AMD.In this review,we described the roles of and changes in TGF-β signaling in the development of AMD and discussed the mechanisms of the TGF-β superfamily in choroidal neovascularization (CNV) and wet AMD,including the modulation of angiogenesis-related factors,inflammation,vascular fibrosis,and immune responses,as well as cross-talk with other signaling pathways.These remarkable findings indicate that TGF-β signaling is a potential target for wet AMD treatment.     

A novel TRPC6-dependent mechanism of TGF-β-induced migration and invasion of human hepatocellular carcinoma cells

正Mechanisms on cancer cell migration and invasion have been major topics of cancer research and anti-cancer therapy development. Among the multiple cell signaling pathways involved in cell migration, those elicited by transforming growth factorβ(TGF-β) have attracted tremendous attention. The TGF-βpolypeptide cytokines include four isoforms:TGF-β1, TGF-β2, TGF-β3, and TGF-β4, which are secreted mainly from cells of white blood cell lineage, such as macrophages, T cells and platelets. However, TGF-βcan also be synthesized and released from fibroblasts and cancer     

Downregulation of CD4＋CD25＋ regulatory T cells may underlie enhanced Th1 immunity caused by immunization with activated autologous T cells

Regulatory T cells （Treg） play important roles in immune system homeostasis, and may also be involved in tumor immunotolerance by suppressing Th1 immune response which is involved in anti-tumor immunity. We have previously reported that immunization with attenuated activated autologous T cells leads to enhanced anti-tumor immunity and upregulated Thl responses in vivo. However, the underlying molecular mechanisms are not well understood. Here we show that Treg function was significantly downregulated in mice that received immunization of attenuated activated autologous T cells. We found that Foxp3 expression decreased in CD4＋CD25＋ T cells from the immunized mice. Moreover, CD4＋CD25＋Foxp3＋ Treg obtained from immunized mice exhibited diminished immunosuppression ability compared to those from naive mice. Further analysis showed that the serum of immunized mice contains a high level ofanti-CD25 antibody （about 30 ng/ml, p〈0.01 vs controls）. Consistent with a role ofanti-CD25 response in the downregulation of Treg, adoptive transfer of serum from immunized mice to naive mice led to a significant decrease in Treg population and function in recipient mice. The triggering of anti-CD25 response in immunized mice can be explained by the fact that CD25 was induced to a high level in the ConA activated autologous T cells used for immunization. Our results demonstrate for the first time that immunization with attenuated activated autologous T cells evokes anti-CD25 antibody production, which leads to impeded CD4＋CD25＋Foxp3＋ Treg expansion and function in vivo. We suggest that dampened Treg function likely contributes to enhanced Thl response in immunized mice and is at least part of the mechanism underlying the boosted anti-tumor immunity.     

Different effect of glutamine on macrophage tumor necrosis factor-alpha release and heat shock protein 72 expression in vitro and in vivo

Macrophage plays a vital role in sepsis. However, the modulatory effect of glutamine （Gin） on macrophage/ monocyte-mediate cytokines release is still controversial. Thus, we investigated the effect of Gin on macro- phage tumor necrosis factor （TNF）-α release and heat shock protein （HSP） 72 expression in vivo and in vitro. Data from our study indicated that the increase of HSP72 expression was significant at 8 mM of Gin 4 h after lipopolysaccharide （LPS） stimulation and became independent of Gin concentrations at 24 h, whereas TNF-α release was dose-and time-dependent on Gin. Heat stress （HS） induced more HSP72 and less TNF-α production compared with the non-HS group. However, the production of TNF-α in cells pretreated with HS was increased with increasing concentrations of Gin. Treatment with various concentrations of Gin for 1 h and then 0.5mM Gin for 4h led to an increase in HSP72 expression, but not in TNF-α production. In sepsis model mice, Gin treatment led to a significantly lower intracellular TNF-α level and an increase in HSP72 expression in mouse peritoneal macrophages. Our results demonstrate that Gin directly increases TNF-α release of LPS-stimulated RAW264.7 macro- phages in a dose-dependent manner, and also decreases mouse peritoneal macrophages TNF-α release in the sepsis model. Taken together, our data suggest that there may be more additional pathways by which Gin modulates cytokine production besides HSP72 expression in macrophage during sepsis.     

Inflammation-induced CD69~+ Kupffer cell feedback inhibits T cell proliferation via membrane-bound TGF-β1

Kupffer cells,tissue-resident macrophage lineage cell,are enriched in vertebrate liver.The mouse F4/80~+ Kupffer cells have been subclassified into two subpopulations according to their phenotype and function:CD68~+ subpopulation with potent reactive oxygen species(ROS) production and phagocytic capacities,and CD11b~+ subpopulation with a potent capacity to produce T helper 1 cytokines.In addition,CD11b~+ Kupffer cells/macrophages may be migrated from the bone marrow or spleen,especially in inflammatory conditions of the liver.For analyzing diverse Kupffer cell subsets,we infected mice with Listeria monocytogenes and analyzed the phenotype variations of hepatic Kupffer cells.During L.monocytogenes infection,hepatic CD69~+ Kupffer cells were significantly induced and expanded,and CD69~+ Kupffer cells expressed higher level of CD11 b,and particularly high level of membrane-bound TGF-β1(mTGF-β1) but lower level of F4/80.We also found that clodronate liposome administration did not eliminate hepatic CD69~+ Kupffer cell subset.We consider the hepatic CD69~+ Kupffer cell population corresponds to CD11b~+Kupffer cells,the bone marrow-derived population.Hepatic CD69~+ Kupffer cells suppressed Ag-nonspecific and OVA-specific CD4 T cell proliferation through mTGF-β1 both in vitro and in vivo,meanwhile,they did not interfere with activation of CD4 T cells.Thus,we have identified a new subset of inflammation-induced CD69~+ Kupffer cells which can feedback inhibit CD4 T cell response via cell surface TGF-β1 at the late stage of immune response against infection.CD69~+ Kupffer cells may contribute to protect host from pathological injure by preventing overactivation of immune response.