Endotoxin activation of endothelium for polymorphonuclear leucocyte transendothelial migration and modulation by interferon-gamma.

Endotoxin [lipopolysaccharide (LPS)] is a potent inflammatory stimulus and can activate human umbilical vein endothelium (HUVE) for leucocyte adhesiveness and transendothelial migration. Here we investigated the role of HUVE-secreted cytokines in this process. When HUVE monolayers were grown on filters and preincubated for 3 hr with LPS, 51Cr-labelled polymorphonuclear leucocytes (PMNL) migrated across the HUVE in a dose- and time-dependent manner. Maximal PMNL transmigration with LPS (1 ng/ml) was 26 +/- 3% of added PMNL in 75 min. Neutralizing antibodies to interleukin-1 alpha (IL-1 alpha) and IL-1 beta, tumour necrosis factor-alpha (TNF-alpha), IL-8 or recombinant IL-1 receptor antagonist had no effect on the activation by LPS of the HUVE for supporting migration of PMNL. The HUVE 'activated state' declined with prolonged (22 hr) exposure to LPS, as reflected by a decrease in PMNL transendothelial migration to 5.5 +/- 1% and in the expression of the endothelial cell adhesion molecule, E-selectin, as compared to stimulation with LPS for 3 hr. However, simultaneous exposure to interferon-gamma (IFN-gamma) (200 IU/ml) and LPS maintained maximal PMNL transendothelial migration (28 +/- 4%) for at least 24 hr, prolonged E-selectin expression by HUVE and superinduced intracellular adhesion molecule-1 (ICAM-1) expression. The PMNL transendothelial migration was blocked by > 90% by monoclonal antibody (mAb) to CD18 with either 3 hr of LPS or 22 hr LPS + IFN-gamma stimulation. Migration was partially inhibited by mAb to E-selectin (30-40%) or to ICAM-1 (35-45%) and by a combination of both reagents (50-60%) under both stimulation conditions. Thus, LPS activation of HUVE for PMNL transendothelial migration: (a) does not require secretion of IL-1, TNF-alpha or IL-8 by the endothelium, (b) IFN-gamma enhances and prolongs endothelial activation by LPS and may increase leucocyte infiltration in LPS or bacterial inflammatory reactions, and (c) CD18-dependent mechanisms are equally important for PMNL transendothelial migration under both acute (3 hr) and prolonged (22 hr LPS + IFN-gamma) activation of endothelium.     

Transforming growth factor-beta enhances interleukin-6 secretion by intestinal epithelial cells.

Recent reports have suggested that transforming growth factor-beta (TGF-beta) may have an important role in IgA immune responses, e.g. induction of surface IgM+ B cells to commit to IgA. TGF-beta is also an important regulatory cytokine for the maturation of intestinal epithelial cells. Using the IEC-6 rat intestinal epithelial cell line as a model system, TGF-beta 1 was found to enhance interleukin-6 (IL-6) secretion by the IEC-6 cells. The IL-6 was produced in a dose-dependent manner and secretion could be specifically inhibited by an anti-TGF-beta 1 antibody. IL-6 production by the IEC-6 cells was confirmed by using a rabbit anti-mouse IL-6 antibody which completely neutralized the IL-6 present in the IEC-6 cell supernatant. The enhancement of IL-6 secretion was found to involve a low-level enhancement in the expression of RNA for IL-6. The induction of IL-6 secretion was also reversible when TGF-beta was removed. These results suggest that the action of TGF-beta on intestinal epithelial cells may play an important role in immune responses at the intestinal mucosa.     

Transforming growth factor-beta 1 enhances the generation of allospecific cytotoxic T lymphocytes.

We investigated the effects of transforming growth factor-beta 1 (TGF-beta 1) on the proliferation and generation of murine T lymphocytes in vitro. TGF-beta 1 suppressed T- and B-lymphocyte proliferation, mixed lymphocyte reaction (MLR), and the generation of natural killer (NK) cells and lymphokine-activated killer (LAK) cells. On the other hand, TGF-beta 1 significantly enhanced the generation of allospecific cytotoxic T lymphocytes (CTL) at low concentrations (0.01-1 ng/ml) in a dose-dependent manner and restored it to the control level at higher concentrations (10-40 ng/ml). Allospecific CTL generation by TGF-beta 1 was maximally enhanced when added at the beginning of culture. Less enhancement occurred when the addition was delayed. Anti-TGF-beta 1 antibody completely abolished the enhancing effects of TGF-beta 1. Furthermore, platelet-derived TGF-beta (pTGF-beta) as well as recombinant TGF-beta 1 similarly enhanced the generation of allospecific CTL. These data demonstrate that TGF-beta has not only immunosuppressive effects but also immuno-enhancing effects in vitro.     

Transforming growth factor-beta 1 enhances IgG and IgA sheep red blood cell responses.

Antibody responses to ingested antigens can be inhibited by a mechanism known as oral tolerance which acts to prevent excessive stimulation from luminal contents. Local IgA responses can be induced in this non-responsive environment and during intestinal inflammation, mucosal IgG responses can also be increased. The purpose of this study was to compare a panel of cytokines to factors from macrophage-T cell co-culture supernatants for their ability to enhance isotype and sheep red blood cell (SRBC)-specific plaque-forming cell responses in an in vitro model of oral tolerance. IL-2, IL-4, IL-5, and IL-6, which have been implicated in IgA regulation of lipopolysaccharide-stimulated B cells, were not capable of enhancing responses in tolerized cultures; however, transforming growth factor (TGF)-beta 1 had a dose-dependent ability to enhance responses to the T cell-dependent antigen SRBCs in this system. The enhancement was only seen when antigen was present and was neutralized by specific rabbit antiserum but not normal rabbit IgG. Similar treatment of soluble factors from the macrophage-T cell co-cultures did not inhibit their ability to enhance responses suggesting at least two distinct molecular mechanisms could augment responses in tolerized cultures. This was substantiated further by showing that TGF-beta 1 was not isotype-specific. In contrast, adsorption of the macrophage-T cell co-culture supernatants against monoclonal IgA or IgG removed isotype-specific binding factors which were necessary for the enhancement of IgA and IgG respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transforming growth factor-beta1 in inflammatory airway disease: a key for understanding inflammation and remodeling

Airway diseases such as chronic rhinosinusitis, asthma, and chronic obstructive pulmonary disorder are characterized by inflammation and remodeling. Among inflammatory and extracellular matrix regulatory cytokines, transforming growth factor-beta (TGF-β) stands central, as it possesses both important immunomodulatory and fibrogenic activities, and should be considered a key for understanding inflammation and remodeling processes. This review will briefly summarize the recent findings on the role of TGF-β1, from the view points of inflammation and remodeling, and discuss the role of TGF-β in the upper and lower airway diseases. This may reveal new perspectives in the understanding of airway inflammation and remodeling processes and may open innovative treatment strategies for the regulation of TGF-β1.     

Transforming growth factor-beta3-loaded microtextured membranes for skin regeneration in dermal wounds

Adverse effects of wound healing, such as excessive scar tissue formation, wound contraction, or nonhealing wounds represent a major clinical issue in today's healthcare. Transforming growth factor (TGF)-beta3 has specifically been implicated in wound healing. Our hypothesis was that local administration of TGF-beta3 to excisional dermal wounds would diminish wound contraction and scar formation. Microtextured wound covers, containing different concentrations of TGF-beta3, were placed onto full-thickness excisional skin wounds in guinea pigs. Tattooed reference marks were used to quantify wound contraction. Sixty-four male guinea pigs in four study groups (5 ng TGF-beta3, 50 ng TGF-beta3, no growth factor, sham wound) were followed for up to 6 weeks. We analyzed 19 different parameters of wound healing. Results showed that, in some instances, the 50-ng TGF-beta3 group gave less contraction, whereas the 5-ng TGF-beta3 group gave more contraction. These differences confirm that TGF-beta3 has an optimum working concentration, and suggest this concentration to be closer to 50 ng than to 5 ng TGF-beta3. However, only very few significant differences occurred, and thus we conclude that the clinical relevance of our findings is negligible. Earlier studies, reporting clinically improved wound healing by TGF-beta3, could therefore not be confirmed by this study.     

Transforming growth factor-beta synthesis by human peritoneal mesothelial cells. Induction by interleukin-1.

Peritoneal mesothelial cells are uniquely located to regulate cellular events in the peritoneal cavity and are a potentially important source for various cytokines. The present study was designed to elucidate the capacity of human peritoneal mesothelial cells (HPMCs) to synthesize and secrete the transforming growth factor (TGF)-beta isoforms 1, 2, and 3 and to characterize their regulation by inflammatory cytokines. HPMCs constitutively released appreciable amounts of TGF-beta 1 and low amounts of TGF-beta 2 as detected by specific immunoassays. TGF-beta 1 levels secreted within 48 hours (45 +/- 8.9 pg/10(5) cells) were 60-fold higher than TGF-beta 2 levels (0.9 +/- 0.1 pg/10(5) cells), respectively. Treatment of HPMCs with interleukin (IL)-1 beta (10 ng/ml) resulted in a significant increase of both TGF-beta 1 (mean, 5-fold; P < 0.001) and TGF-beta 2 (mean, 6-fold; P < 0.01) generation. After 48 hours of IL-1 beta treatment the levels were 185 +/- 17.1 pg/10(5) cells for TGF-beta 1 and 5.3 +/- 1.5 pg/10(5) cells for TGF-beta 2, respectively. Neither tumor necrosis factor (TNF)-alpha nor interferon (IFN)-gamma (both 10 ng/ml) affected TGF-beta 1 or TGF-beta 2 synthesis by HPMCs. TGF-beta 3 could not be detected in any of the supernatant media. Stimulation of HPMCs with IL-1 beta increased steady-state levels of TGF-beta 1- and TGF-beta 2-specific mRNA. Western blot analysis of supernatants revealed the presence of an immunoreactive band at 25 kd. Indirect competition assays confirmed receptor-binding activity of HPMC-derived TGF-beta. Appreciable amounts of TGF-beta were present in a bioactive form. Our results demonstrate that HPMCs synthesize the TGF-beta isoforms 1 and 2 and that the levels of mRNA and protein release can be up-regulated by the proinflammatory cytokine IL-1 beta.     

Transforming growth factor-beta produced by progressor tumors inhibits, while IL-10 produced by regressor tumors enhances, Langerhans cell migration from skin

The induction of epidermal immunity depends on activation of local dendritic cells (DC), Langerhans cells (LC), to migrate from the skin to local lymph nodes and mature into potent immunostimulatory cells. We have previously shown that progressor skin tumors, which evade immunological destruction, prevent contact sensitizer-induced LC migration from the skin to draining lymph nodes. In contrast, regressor tumors, which evoke protective immunity, did not inhibit DC mobilization. In this study we utilized the skin explant model to determine the factors produced by skin tumors which regulate LC migration from the skin. Supernatants from two progressor squamous cell carcinoma lines both inhibited LC migration, whereas supernatants from two regressor squamous cell carcinoma lines both enhanced LC mobilization. Transforming growth factor (TGF)-beta1 inhibited, while IL-10 enhanced, LC migration from cultured skin. Both reduced the ability of LC to mature into potent allostimulators. Antibody neutralization identified that TGF-beta1 produced by the progressor tumor was responsible for inhibition of LC migration, while IL-10 produced by the regressor tumor enhanced LC mobilization. Thus these studies show that skin tumors influence DC mobilization from tumors by production of cytokines, and that TGF-beta1 is one factor produced by tumors which can immobilize LC and keep them in an immature form. This is likely to be an important mechanism of tumor escape from the immune system as progressor tumors inhibited, while regressor tumors enhanced DC mobilization.     

Tumour necrosis factor-alpha but not interleukin-1 induces polymorphonuclear leucocyte migration through fibroblast layers by a fibroblast-dependent mechanism.

Interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF-alpha) both induce polymorphonuclear leucocyte (PMNL) infiltration into tissues and they have a synergistic action in this respect. We and others have observed that IL-1 alpha and TNF-alpha induce 51Cr-labelled PMNL migration across monolayers of umbilical vein endothelium via an endothelial cell-dependent mechanism. Here we investigated the interaction of PMNL with fibroblasts, since PMNL probably encounter such cells in many tissues once they traverse the vascular wall. TNF-alpha, but not IL-1 alpha, was found to activate fibroblast monolayers, grown on polycarbonate filters, to stimulate PMNL transfibroblast migration. This was a time- and fibroblast-dependent process which required fibroblast protein synthesis, as indicated by inhibition with cycloheximide. The effect of TNF-alpha was not related to fibroblast chemotactic factor production (primarily IL-8), or to ICAM-1 up-regulation, since IL-1 was as active as TNF-alpha in this respect, without activating fibroblasts to support PMNL transfibroblast migration. Antiserum to IL-8, present during the assay, did not inhibit PMNL migration across the monolayers. The PMNL migration was highly dependent on the function of both CD11a (LFA-1) and CD11b (MAC-1) PMNL adhesion molecules, since monoclonal antibodies to either inhibited migration by about 80%. The results suggest a distinct activation by TNF-alpha of fibroblasts to facilitate PMNL migration through fibroblast barriers. These findings may in part account for the synergistic action of IL-1 and TNF-alpha in inducing extravascular accumulation of PMNL during inflammation.     

退行性变椎间盘组织转化生长因子β1基因的表达

背景：据报道,转化生长因子β1能促进椎间盘细胞的增殖与分化,并参与其损伤修复过程。但转化生长因子β1是否参与椎间盘退变的过程？ 目的：分析在人体退行性变椎间盘组织中转化生长因子β1的表达情况,并探讨其与人体椎间盘退行性变的关系。 方法：收集正常椎间盘组织30例,退行性变人体椎间盘组织530例,采用苏木精-伊红染色、免疫印迹和RT-PCR方法进行研究,对退行性变的椎间盘组织进行病理学分型,分别检测转化生长因子β1在不同类型退变的椎间盘中表达的情况并与正常椎间盘组织进行对比分析。 结果与结论：苏木精-伊红染色病理学诊断：将退行性变的椎间盘组织根据病理学改变程度分为4型。免疫印迹法和RT-PCR法均显示：在正常和退变椎间盘组织中,转化生长因子β1均有表达,但在病变组织中随病变加重转化生长因子β1表达量随之增加,退变组织与正常组织比较差异有非常显著性意义 (P < 0.01)。说明转化生长因子β1高表达与人体椎间盘退行性变呈正相关。     

Transforming growth factor-beta1 inhibits steroidogenesis in human trophoblast cells

Transforming growth factor-beta (TGF-beta) is an important regulator of placental development and function. In this study, we have investigated the effect of TGF-beta1 on steroidogenesis, as well as its sites of action in the steroidogenic pathway by using a choriocarcinoma cell line, JEG-3, and a normal trophoblast cell line (NPC). The effect of TGF-beta1 on progesterone and estradiol production was evaluated in the absence or presence of a membrane-permeable analogue of cholesterol and some intermediate substrates of steroidogenic enzymes. The effect of TGF-beta1 on P450 aromatase (P450arom) mRNA levels was determined by Northern blot analysis. TGF-beta1 significantly decreased progesterone production in both NPC and JEG-3 cells. The inhibitory effect of TGF-beta1 on progesterone production was reversed by addition of 22R-hydroxycholesterol, a membrane-permeable analogue of cholesterol, or pregnenolone. In JEG-3 cells, TGF-beta1 also inhibited estradiol production when androstenedione, but not estrone, was added to the culture. Estradiol production was too low to be detected in NPC cells. Treatment with TGF-beta1 also suppressed aromatase mRNA levels. This study has demonstrated that TGF-beta1 inhibits progesterone and estradiol production by trophoblast cells, and that the sites of TGF-beta1 action on progesterone and estradiol production are likely to be cholesterol transport and P450arom respectively.     

Transforming growth factor-beta signaling in normal and malignant hematopoiesis.

Transforming growth factor-beta (TGF-beta) is an important physiologic regulator of cell growth and differentiation. TGF-beta has been shown to inhibit the proliferation of quiescent hematopoietic stem cells and stimulate the differentiation of late progenitors to erythroid and myeloid cells. Insensitivity to TGF-beta is implicated in the pathogenesis of many myeloid and lymphoid neoplasms. Loss of extracellular TGF receptors and disruption of intracellular TGF-beta signaling by oncogenes is seen in a variety of malignant and premalignant states. TGF-beta can also affect tumor growth and survival by influencing the secretion of other growth factors and manipulation of the tumor microenvironment. Recent development of small molecule inhibitors of TGF-beta receptors and other signaling intermediaries may allow us to modulate TGF signaling for future therapeutic interventions in cancer.     

Transforming growth factor-beta 1 in experimental autoimmune neuritis. Cellular localization and time course.

Experimental autoimmune neuritis (EAN) is a monophasic inflammatory disorder of the peripheral nervous system that resolves spontaneously by molecular mechanisms as yet unknown. We have investigated whether the immunosuppressive cytokine transforming growth factor-beta 1 (TGF-beta 1) might be endogenously expressed in the peripheral nervous system of Lewis rats with actively induced and adoptive transfer EAN. TGF-beta 1 mRNA was upregulated to high levels in sensory and motor roots, spinal ganglia, and sciatic nerve as revealed by quantitative Northern blot analysis and in situ hybridization histochemistry, with peak levels just preceding the first signs of clinical recovery. TGF-beta 1 mRNA was localized to scattered round cells and dense cellular infiltrates, but only rarely to Schwann cell profiles. Double labeling studies revealed macrophages and subpopulations of T cells as the major cellular source of TGF-beta 1 mRNA. TGF-beta 1 protein was visualized immunocytochemically and localized to infiltrating mononuclear cells with peak expression around the same time as mRNA, in addition to some constitutive expression in axons and Schwann cells. Our studies suggest that the spontaneous recovery observed in Lewis rat EAN might be mediated by the endogenous elaboration of TGF-beta 1 within the peripheral nerve, and that macrophages might control their own cytotoxicity by expressing TGF-beta 1.     

Transforming growth factor-beta 1 in rheumatoid synovial membrane and cartilage/pannus junction.

Transforming growth factor (TGF)-beta has been shown to promote tissue repair and have immunosuppressive actions, and has been proposed to have a role in rheumatoid arthritis (RA). Using immunohistochemical techniques with rabbit F(ab')2 antibodies raised against recombinant human TGF-beta 1, we have detected TGF-beta 1 in the synovial tissue and cartilage/pannus junction (CPJ) from 18/18 patients with RA. TGF-beta 1 was found predominantly in the thickened synovial lining layer in RA, but also detected in a perivascular pattern in the synovial interstitium as well as in occasional cells in the lymphoid aggregates. At the CPJ it was found both in cells at the distinct junction as well as in the transitional region of the diffuse fibroblastic zone. The cells staining for TGF-beta 1 were identified by double immunofluorescence staining as being from the monocyte/macrophage series as well as the type B synovial lining cells. TGF-beta 1 was also detected in the synovial membrane sections from 4/4 patients with systemic lupus erythematosus/mixed connective tissue disease and 5/8 patients with osteoarthritis, in a similar distribution to that seen in RA, and in the lining layer of 1/7 normal synovial membranes. These results add to histological evidence confirming that TGF-beta 1 is present in RA synovial cells and those from other arthritides. The distributions of TGF-beta 1 in RA synovial membrane reflects its known actions, as it can be detected at the CPJ, where it could induce repair, and close to activated cells upon which it may exert an immunosuppressive action.     

Transforming growth factor-beta1 induces transforming growth factor-beta1 and transforming growth factor-beta receptor messenger RNAs and reduces complement C1qB messenger RNA in rat brain microglia

Transforming growth factor-beta1 is a multifunctional peptide with increased expression during Alzheimer's disease and other neurodegenerative conditions which involve inflammatory mechanisms. We examined the autoregulation of transforming growth factor-beta1 and transforming growth factor-beta receptors and the effects of transforming growth factor-beta1 on complement C1q in brains of adult Fischer 344 male rats and in primary glial cultures. Perforant path transection by entorhinal cortex lesioning was used as a model for the hippocampal deafferentation of Alzheimer's disease. In the hippocampus ipsilateral to the lesion, transforming growth factor-beta1 peptide was increased >100-fold; the messenger RNAs encoding transforming growth factor-beta1, transforming growth factor-beta type I and type II receptors were also increased, but to a smaller degree. In this acute lesion paradigm, microglia are the main cell type containing transforming growth factor-beta1, transforming growth factor-beta type I and II receptor messenger RNAs, shown by immunocytochemistry in combination with in situ hybridization. Autoregulation of the transforming growth factor-beta1 system was examined by intraventricular infusion of transforming growth factor-beta1 peptide, which increased hippocampal transforming growth factor-beta1 messenger RNA levels in a dose-dependent fashion. Similarly, transforming growth factor-beta1 increased levels of transforming growth factor-beta1 messenger RNA and transforming growth factor-beta type II receptor messenger RNA (IC(50), 5pM) and increased release of transforming growth factor-beta1 peptide from primary microglia cultures. Interactions of transforming growth factor-beta1 with complement system gene expression are also indicated, because transforming growth factor-beta1 decreased C1qB messenger RNA in the cortex and hippocampus, after intraventricular infusion, and in cultured glia. These indications of autocrine regulation of transforming growth factor-beta1 in the rodent brain support a major role of microglia in neural activities of transforming growth factor-beta1 and give a new link between transforming growth factor-beta1 and the complement system. The auto-induction of the transforming growth factor-beta1 system has implications for transgenic mice that overexpress transforming growth factor-beta1 in brain cells and for its potential role in amyloidogenesis.     

Activation of brain endothelium by Escherichia coli K1 virulence factor cglD promotes polymorphonuclear leukocyte transendothelial migration

Medical Microbiology and Immunology - Escherichia coli K1 is the most common Gram-negative bacteria causing neonatal meningitis. Polymorphonuclear leukocyte (PMN) transmigration across the...     

Transforming growth factor-beta 1 and insulin-like growth factor-1 expression in ovarian endometriotic cysts: a preliminary study

Increased concentrations of TGF-beta 1 in endometriotic tissue are considered important in the pathophysiology of endometrial diseases since TGF-beta 1 may inhibit natural killer activity and induce angiogenesis and proliferation of endometrial stromal cells. In the present study we report on TGF-beta 1, IGF-1 and their receptor localization, as detected by Northern hybridization and immunohistochemistry, in ovarian endometriotic tissues removed during surgical procedures. We detected comparable expression of IGF-1 and IGF-1 receptor in the stromal and epithelial compartments, thus confirming disregulated expression of the IGF system in ovarian endometriosis. On the contrary, strongly increased TGF-beta 1 steady state level mRNA expression was detected in all endometriotic samples. In addition, we demonstrated weak TGF-beta 1 immunohistochemical expression in the epithelial lining and intense expression in the cellular stroma of ovarian endometriomas, thus suggesting that TGF-beta 1 could have an important role in the maintenance and propagation of the disease. On the basis of these preliminary results we can assume that TGF-beta 1, IGF-1 and their receptors may play an important role in the pathogenesis of endometriosis.