Transforming growth factor beta (TGF-beta) in inflammation: a cause and a cure

Constitutive and LPS-induced gene expression in a macrophage-like cell line from the rainbow trout (Oncorhynchus mykiss)

The lack of cell lines from mononuclear phagocytes of salmonid fish has impeded the study of immune function at a cellular level in these economically and ecologically important animals. Here, we report on the further characterization of RTS11, a previously described macrophage-like cell line from the rainbow trout spleen, with regard to its expression of a number of immunologically relevant genes. Analysis of gene expression by reverse transcription-polymerase chain reaction, using rainbow-trout-specific primers demonstrated that RTS11 cells express the beta chain of the class II major histocompatibility complex, the cytokines transforming growth factor-beta (TGF-beta) and interleukin-1beta (IL-1beta), and cyclo-oxygenase-2 (COX-2). Inducing the cells with lipopolysaccharide led to increased expression of IL-1beta and COX-2, as determined by Northern blotting. These results together suggest that RTS11 retains many of the characteristics expected of mature macrophages, and should be a valuable tool for further study of the expression and function of these immunomodulatory proteins in fish.

Cytokines in WBC-reduced apheresis PCs during storage: a comparison of two WBC-reduction methods

BACKGROUND

Several studies have suggested that cytokine accumulation during storage of platelet concentrates (PCs) may mediate nonhemolytic febrile transfusion reactions and that a reduction in WBC numbers prevents the generation of cytokines. Despite efforts to minimize WBC contamination in apheresis PCs, high numbers of WBCs and increased cytokine levels may still occur, depending on the quality of the apheresis device employed.

STUDY DESIGN AND METHODS

This study was undertaken to investigate whether PCs collected with WBC-reduction devices (Spectra LRS, COBE;or MCS+ LDP, Haemonetics) were sufficiently depleted of WBCs to limit cytokine accumulation during storage. The study evaluated 1) the levels of cytokines of WBC and platelet origin in two types of apheresis PCs during storage and 2) the effects of prestorage filtration on cytokine levels in the Spectra LRS PCs.

RESULTS

In the Spectra LRS PCs, low levels of IL-6, IL-8, and monotype chemoattractant protein 1 (MCP-1) were detected in Day 1 PCs, and they remained consistent during the shelf life. RANTES, platelet factor 4 (PF4), beta-thromboglobulin (beta-TG), and transforming growth factor (TGF)-beta1 were also detected in these PCs, and their levels increased significantly on storage. Prestorage filtration of Spectra LRS PCs did not further reduce the levels of IL-6, IL-8, MCP-1, PF4, beta-TG, and TGF-beta1 in the filtered component. In the MCS+ LDP PCs, IL-6 was detected on Day 1, and its level increased significantly on storage, whereas the levels in the Spectra PCs remained steady. IL-8 levels were lower in MCS+ LDP PCs than in Spectra LRS PCs of the same age. MCP-1 levels were similar in both products on Day 1 and marginally increased in stored MCS+ LDP PCs. Substantial amounts of RANTES, PF4, beta-TG, and TGF-beta1 occurred in Day 1 MCS+ LDP PCs, and, on storage, these levels rose significantly.

CONCLUSION

Despite a significant reduction in levels of WBC-derived cytokines, platelet-derived cytokines were present in different amounts in the two products.

Transforming growth factor-beta induces apoptosis in activated murine T cells through the activation of caspase 1-like protease

Transforming growth factor-beta (TGF-beta) has been known as a potent immunosuppressive cytokine that can induce apoptosis in lymphoid cells. We established an IL-2-independent cell line, CTLL-2A, from murine T cell line CTLL-2. CTLL-2A expressed higher levels of CD95, CD69, and CD18 molecules than CTLL-2 did, suggesting a more activated state in CTLL-2A than in the CTLL-2 by phenotype. Exposing both CTLL-2 and CTLL-2A to TGF-beta results in differential apoptosis patterns defined by DNA fragmentation and plasma membrane alteration. Among the bcl-2 family members, bcl-2, bcl-w, and bcl-x(L) were also differently expressed in these two cell lines. In CTLL-2A, bcl-x(L) was amplified as a major anti-apoptotic molecule, and TGF-beta-induced cell death was more enhanced than in the original cell line. Caspase 1-like protease was activated by TGF-beta treatment and consequently it cleaved bcl-x(L) in CTLL-2A. TGF-beta-induced DNA fragmentation and cleavage of bcl-x(L) were inhibited by pretreatment with tetra peptide caspase 1 inhibitor, YVAD.cmk. These findings suggest that TGF-beta induces cell death in activated murine T cells through cleavage of bcl-x(L) via activated caspase 1-like protease, which may act as an important executor in that process.

Cytokine accumulation in stored red cell concentrates: effect of buffy-coat removal and leucoreduction

The accumulation of cytokines in stored red blood cell concentrates (RCCs) has been implicated as a potential cause of transfusion reactions associated with the use of such products. At present, it is unclear whether there is any link between residual leukocyte and/or platelet content with cytokine levels in various RCCs. In this study, we have therefore assessed cytokine levels of leukocyte (e.g., IL8) and platelet (e.g., RANTES, TGF-beta1) origin in supernatants of RCCs prepared by the plasma reduced method or by depletion of the buffy coat. We have also assessed whether the Duffy antigen receptor (DARC, a promiscuous receptor for some chemokines) has any role in the diminution of cytokine levels in stored blood components by comparing cytokine levels in stored plasma reduced RCCs derived from both DARC +ve and DARC -ve individuals. In addition, comparison of filtered and non-filtered products of the same origin has also been conducted. Results showed that supernatants from DARC -ve concentrates contained higher levels of IL-8 up to days 14/15 of storage compared with DARC +ve RCCs. However, at later time points, similar levels of IL-8 were observed in RCCs regardless of their Duffy receptor status. For TGF-beta1 and RANTES, no significant difference in the levels of these cytokines was detected between DARC +ve and DARC -ve concentrates. Removal of leukocytes and platelets by conventional leukocyte filtration significantly reduced the accumulation of cytokines. Buffy coat reduced RCCs contained minimal amounts of IL-8 and TGF-beta1 but no RANTES. We conclude therefore, that the levels of cytokines in the supernatants of RCCs stored at 4 degrees C are related mainly to their leucocyte and platelet content.

TGF-beta 1 differentially regulates IL-2 expression and [3H]-thymidine incorporation in CD3 epsilon mAb- and CD28 mAb-activated splenocytes and thymocytes

Transforming growth factor-beta(1) (TGF-beta(1)) is a critical bifunctional regulator of inflammatory responses. Evidence strongly suggests that these regulatory consequences are, at least in part, a result of profound pleiotropic effects on T lymphocyte effector function. The mechanisms underlying the contradictory biological effects of TGF-beta(1) remain ambiguous. The objective of the present studies was to test the hypothesis that the concentration of TGF-beta(1) and the temporal relationship between activation of the T cell receptor (TCR) and the TGF-beta receptor regulate the effect of TGF-beta(1) on T lymphocyte activation and proliferation. Toward this end, we have quantified the concentration- and time-dependent effect of TGF-beta(1) on interleukin-2 (IL-2) protein secretion as an index of T lymphocyte activation and [3H]-thymidine incorporation as an index of cell proliferation in primary splenocytes and thymocytes. Our results suggest that TGF-beta(1) stimulates IL-2 production at low concentrations (0.1-1 pg/ml) and conversely inhibits IL-2 production at high concentrations (1-10 ng/ml) in CD3epsilon monoclonal antibody (mAb)+/-CD28 mAb-activated splenocytes. Additionally, concentrations of TGF-beta(1) that stimulate IL-2 production in CD3epsilon mAb+CD28 mAb-activated splenocytes concominantly inhibit splenocyte proliferation under similar conditions. Furthermore, we provide evidence suggesting that the effects of TGF-beta(1) on T lymphocytes are dependent upon the temporal relationship between activation of the TCR and the TGF-beta receptor. A time-dependent loss of a stimulatory effect and a concomitant gain of an inhibitory response by TGF-beta(1) on IL-2 production in response to CD3epsilon and CD28 mAbs is observed when TGF-beta(1) is added following T lymphocyte activation. In summary, these data unequivocally demonstrate that the orchestration of paradoxical effects of TGF-beta(1) on T-lymphocyte function is dependent upon the concentration of TGF-beta(1) and the temporal relationship between activation of signaling through the TCR and the TGF-beta receptor. Future mechanistic studies addressing the putative role that these factors play in modulating the effects of TGF-beta(1) on T lymphocyte activity will undoubtedly provide valuable insight towards the pharmacological intervention of inflammatory responses.

Blockade of transforming growth factor beta/Smad signaling in T cells by overexpression of Smad7 enhances antigen-induced airway inflammation and airway reactivity

Transforming growth factor (TGF)-beta has been implicated in immunosuppression. However, it remains obscure whether regulation of T cells by TGF-beta contributes to the immunosuppression in vivo. To address this issue, we developed transgenic mice expressing Smad7, an intracellular antagonist of TGF-beta/Smad signaling, selectively in mature T cells using a plasmid construct coding a promoter element (the distal lck promoter) that directs high expression in peripheral T cells. Peripheral T cells were not growth inhibited by TGF-beta in Smad7 transgenic mice. Although Smad7 transgenic mice did not spontaneously show a specific phenotype, antigen-induced airway inflammation and airway reactivity were enhanced in Smad7 transgenic mice associated with high production of both T helper cell type 1 (Th1) and Th2 cytokines. Thus, blockade of TGF-beta/Smad signaling in mature T cells by expression of Smad7 enhanced airway inflammation and airway reactivity, suggesting that regulation of T cells by TGF-beta was crucial for negative regulation of the inflammatory (immune) response. Our findings also implicated TGF-beta/Smad signaling in mature T cells as a regulatory component of allergic asthma.

Delayed wound healing in immunodeficient TGF-beta 1 knockout mice

Previous studies showed that full-thickness wounds in transforming growth factor-beta1-deficient mice initially heal normally. Unfortunately, transforming growth factor-beta1 deficiency leads to a multifocal inflammatory disease affecting most organs of the body, which ultimately interferes with later stages of wound healing in these mice. As this inflammatory disease is eliminated in transforming growth factor-beta1-deficient mice lacking T and B cells (Tgfb1-/- Scid-/- mice), we hypothesized that wound repair in the latter would proceed normally, even at later stages of healing. Unexpectedly, Tgfb1-/- Scid-/- mice demonstrate a major delay of approximately 1 wk in each of the major phases of wound healing: inflammation, proliferation, and maturation. Immuno- deficient Scid-/- mice that have the wild-type Tgfb1 allele do not experience this delay in wound healing. One interpretation of these findings is that lymphocytes and transforming growth factor-beta1 affect compensatory pathways in wound healing. An alternative interpretation is that the delayed expression of Tgfb2 and Tgfb3 that occurs in the absence of transforming growth factor-beta1 results in the delayed wound healing, suggesting that transforming growth factor-beta2 and/or transforming growth factor-beta3 play important parts in wound healing.

TGF-beta1 stimulates IL-8 release, COX-2 expression, and PGE(2) release in human airway smooth muscle cells

We have recently shown that endogenous prostanoids are critical in bradykinin-stimulated interleukin (IL)-8 release from human airway smooth muscle (ASM) cells. In this study, we tested the ability of transforming growth factor (TGF)-beta1 to stimulate IL-8 release, cyclooxygenase (COX)-2 expression and PGE(2) generation in cultured human ASM cells and explored the role of COX products and COX-2 induction on IL-8 release. TGF-beta1 stimulated IL-8 release, COX-2 induction, and PGE(2) generation in a concentration- and time-dependent manner. Maximal IL-8 release was achieved with 10 ng/ml of TGF-beta1 after 16 h of incubation, which was inhibited by the transcription inhibitor actinomycin D and the corticosteroid dexamethasone but was not affected by the nonselective COX inhibitor indomethacin and the selective COX-2 inhibitor NS-398 despite their inhibition on TGF-beta1-induced PGE(2) release. These results show for the first time that TGF-beta1 stimulates IL-8 release, COX-2 induction, and PGE(2) generation in human ASM cells and that PGE(2) generation is not critical for TGF-beta1-induced IL-8 release. These findings suggest that TGF-beta1 may play an important role in the pathophysiology of asthma.

Effects of secretory leucocyte protease inhibitor on the production of the anti-inflammatory cytokines, IL-10 and transforming growth factor-beta (TGF-beta), by lipopolysaccharide-stimulated macrophages

We studied the effects of secretory leucocyte protease inhibitor (SLPI) on the production of the anti-inflammatory cytokines, IL-10 and TGF-beta, by lipopolysaccharide (LPS)-stimulated macrophages, using half-sized SLPI (1/2 SLPI) containing the C-terminal domain (Arg58-Ala107). ELISA testing of macrophage culture fluids showed a temporary production of IL-10 by the macrophages in the early phase (24 h) after LPS stimulation at low (1 ng/ml) or high (10 microg/ml) concentrations. On the other hand, TGF-beta production was initiated after day 3 and progressively increased. 1/2 SLPI significantly increased IL-10 and TGF-beta production by macrophages in response to a low dose as well as a high dose of LPS. Reverse transcription-polymerase chain reaction analysis showed that 1/2 SLPI caused a significant increase in the expression of both IL-10 and TGF-beta mRNAs by LPS-stimulated macrophages. Thus, although the profile of macrophage TGF-beta production by LPS-stimulated macrophages is markedly different from that of their IL-10 production, SLPI causes an up-regulation of the production of these anti-inflammatory cytokines by LPS-stimulated macrophages.

Increase in wound breaking strength in rats in the presence of positively charged dextran beads correlates with an increase in endogenous transforming growth factor-beta1 and its receptor TGF-betaRI in close proximity to the wound

We have previously shown that positively charged beads (DEAE A25) increase wound breaking strength in linear incisions in rats and nonhuman primates at days 10-14 post-wounding. The increased wound strength may result in part from a stimulation of cells adjacent to the DEAE A25 beads to produce growth factors important for wound healing. In this report, we investigate this hypothesis by comparing the relative expression levels of transforming growth factor-beta1 and its receptor transforming growth factor-beta receptor type I in DEAE A25-treated and contralateral untreated rat linear incisions. DEAE A25-treated incisions were stronger than untreated control wounds at 3 days post-wounding, and the difference in breaking strength reached statistical significance at days 5, 7 and 10. Immunohistochemical analysis revealed a significant increase in transforming growth factor-beta1 and transforming growth factor-beta receptor type I expression in DEAE A25-treated incisions, up to 7 days post-wounding, as compared to untreated control wounds. FACS analysis revealed that macrophage cell lines exposed to DEAE A25 in vitro upregulate transforming growth factor-beta1 and transforming growth factor-beta receptor type I expression by 2-3 fold. Therefore, the increase in expression of transforming growth factor-beta1 and transforming growth factor-beta receptor type I in DEAE A25-treated incisions may be due to an increase in the concentration of macrophages adjacent to DEAE A25 beads, as well as the stimulation of individual macrophages to produce greater amounts of transforming growth factor-beta1 and transforming growth factor-beta receptor type I. This study also supports the significance of transforming growth factor-beta1 in wound healing.

Evaluation of pooled platelet concentrates using prestorage versus poststorage WBC reduction: impact of filtration timing

BACKGROUND

Concern for the undesirable consequences of transfusing passenger WBCs is leading to the general use of WBC-reduced platelet concentrates (PCs). However, the impact of prestorage versus poststorage WBC reduction on the quality of platelet products has not been clearly defined.

STUDY DESIGN AND METHODS

Pooled PCs were WBC reduced before or after 5-day storage, by use of a WBC filter (PXL-8, Pall Corp.). Samples from pools were taken on days 1 and 5, before and after filtration, and on Day 9 of storage and assessed for cell counts, biochemical values, expression of platelet glycoproteins, thrombin generation, and content of IL-6, IL-8, TNFalpha, transforming growth factor beta1 (TGFbeta1), and anaphylatoxins C3a and C4a.

RESULTS

Filtration of fresh and 5-day-stored pooled PCs via a PXL-8 filter was similarly efficient, rendering pools with low WBC counts (<1 x 10(6) cells) and high platelet recovery (>95%). No major changes were found in the metabolic behavior or the expression of platelet GPIb, GPIIb/IIIa, CD62, and CD63 in PCs filtered before or after storage. Filtration, either before or after storage, increased by less than 5 percent the proportion of CD62+ platelets. Moreover, no changes were found in the concentration of prothrombin fragments 1 and 2 and thrombin-antithrombin complexes in the pooled PCs derived from the time of filtration. Finally, prestorage WBC reduction abrogated the accumulation of IL-6 and IL-8, but it did not prevent that of anaphylatoxins C3a and C4a nor of TGFbeta1. However, filtration through a PXL-8 filter significantly reduced (40-90%) the amount of IL-8, C3a, and C4a in the filtrate.

CONCLUSIONS

The timing of PXL-8 filtration of PCs has little impact on the efficiency of WBC reduction and on platelet recovery, and it does not seem to affect the quality of platelets or the generation of thrombin in the PCs. As regards the goal of reducing the amount of bioactive products in PCs, it remains uncertain as to whether prestorage WBC reduction fully eliminates the need for poststorage filtration. Prestorage filtration leads to low levels of IL-6 and IL-8 in PCs, but it does not impair the poststorage content of TGFbeta1 or anaphyla-toxins. By contrast, poststorage PXL-8 filtration removes significant amounts of C3a and C4a, and thus it might provide clinical benefits beyond those of prestorage WBC reduction.

Dose-dependent changes in influenza virus-infected dendritic cells result in increased allogeneic T-cell proliferation at low, but not high, doses of virus

During the acute phase of infection with influenza A virus, the degree of lymphopenia correlates with severity of disease. Factors that contribute to T-cell activation during influenza virus infection may contribute to this observation. Since the immune response is initiated when dendritic cells (DC) interact with T cells, we have established an in vitro system to examine the effects of influenza virus infection on DC function. Our results show that allogeneic T-cell proliferation was dependent on the dose of A/PR/8/34 used to infect DC, with enhanced responses at low, but not high, multiplicities of infection. The lack of enhancement at high virus doses was not primarily due to the increased rate of DC apoptosis, but required viral replication and neuraminidase (NA) activity. Clusters that formed between DC or between DC and T cells were also dependent on the viral dose. This change in cellular interaction may oppose T-cell proliferation in response to DC infected with high doses of PR8, since the increased contact between DC resulted in the exclusion of T cells. The enhanced alloreactive T-cell response was restored by neutralization of transforming growth factor beta1 (TGF-beta1). It is likely that NA present on viral particles released from DC infected with high doses of PR8 activates TGF-beta1. Future studies will determine the mechanism by which TGF-beta1 modifies the in vitro T-cell response and address the contribution of this cytokine to the lymphopenia observed in severe disease.

Immunolocalization of macrophages and transforming growth factor-beta 1 in induced rat periapical lesions

Apical periodontitis was induced in Wistar rats by exposing the pulp chamber of right mandibular first molars to the oral environment. Animals were killed 0, 5, 10, 15, 20, 30, 60, and 80 days after lesion induction. Microradiographic and automated image analysis showed that the lesions expanded significantly in a time-dependent manner from day 0 to day 20 (0.039 mm2/day, p < 0.05, active phase) and stabilized thereafter (chronic phase). A linear regression test revealed a positive correlation between the numbers of ED-1 positive macrophage per microscopic high power field and the periapical lesion size during the active phase (r = 0.98, p < 0.01). Immunohistochemical studies showed that transforming growth factor-beta 1 positive macrophages distributed around the root apex and areas showing bone resorption during active lesion phase, whereas TGF-beta 1-positive osteoblasts were detected during the chronic stage (days 30, 60, and 80 after pulp exposure). Histologically TGF-beta 1 positive osteoblasts possessed a large, round nucleus as well as an abundant cytoplasm and located in close vicinity to areas exhibiting reparative bone formation. These results suggest that macrophages may play important role(s) in the initiation and development of periapical lesions and TGF-beta 1 may play dual roles in both bone resorption and deposition in induced rat periapical lesions.

TGF-beta1 and radiation fibrosis: a master switch and a specific therapeutic target?

Radiation fibrosis is a frequent sequel of therapeutic or accidental radiation overexposure in normal human tissues. One of the main fundamental problems yet unsolved in fibrotic tissues is the origin of the chronic activation of myofibroblasts within these tissues. It has been postulated that this chronic activation results from a continuous production of activating factors. In this context, fibrosis could be defined as a wound where continuous signals for tissue repair are emitted. Cytokines and growth factors probably play a central role in this process. Among them, transforming growth factor-beta1 (TGF-beta1) is considered as a master switch for the fibrotic program. This review discusses recent evidence on the critical role played by TGF-beta in the initiation, development, and persistence of radiation fibrosis. It summarizes the results concerning this factor after irradiation of various tissues and cells, with an emphasis on superficial fibrosis, including skin and subcutaneous tissues. Finally, recent data concerning the treatment of established fibrotic disorders of various etiology are presented, as well as the possible mechanisms involved in fibrosis regression, which show that the TGF-beta pathway may constitute a specific target for antifibrotic agents.

Changes of cytokine profiles during peritonitis in patients on continuous ambulatory peritoneal dialysis

Continuous ambulatory peritoneal dialysis (CAPD) has emerged as an important dialysis treatment modality worldwide. One of the major complications is bacterial peritonitis, which may result in subsequent technique failure because of loss of peritoneal clearance or peritoneal fibrosis. Bacterial peritonitis leads to the release of proinflammatory cytokines from resident and infiltrating cells in the peritoneal cavity. We studied 35 patients undergoing CAPD with acute bacterial peritonitis. All patients treated with antibiotics for 2 weeks after the clinical diagnosis of peritonitis had a good recovery. Peritoneal dialysate effluent (PDE) was collected on days 1, 3, 5, 10, 21, and 42 after the start of treatment. Cell populations were monitored by flow cytometry. PDE levels of interleukin-1beta (IL-1), IL-6, transforming growth factor-beta (TGF-beta), and basic fibroblast growth factor (FGF) were measured by enzyme-linked immunosorbent assay. Gene transcription of TGF-beta in macrophages from PDE was measured by quantitative polymerase chain reaction. Bacterial peritonitis was associated with a sharp increase in total cell and neutrophil counts (400-fold) in PDE up to 3 weeks after peritonitis despite clinical remission (P < 0.0001). There was an increased absolute number of macrophages during the first 3 weeks despite the reduced percentage of macrophages among total cells in PDE compared with noninfective PDE. There was a progressive increase in the percentage of mesothelial cells or dead cells in the total cell population in PDE over the entire 6-week period. PDE levels of IL-1, IL-6, TGF-beta, and FGF increased markedly on day 1 before their levels decreased gradually. PDE levels of these cytokines or growth factors were significantly greater than those in noninfective PDE (n = 76) throughout the study period (P < 0.01). Similarly, TGF-beta complementary DNA (cDNA) molecules per macrophage were significantly greater than those of macrophages in noninfective PDE throughout this period (P < 0.01). There was no significant correlation between PDE levels of TGF-beta and TGF-beta cDNA molecules per macrophage, suggesting that peritoneal macrophages are not the only source of TGF-beta in PDE. We conclude there is an active release of proinflammatory cytokines and sclerogenic growth factors through at least 6 weeks despite apparent clinical remission of peritonitis. The peritoneal cytokine networks after peritonitis may potentially affect the physiological properties of the peritoneal membrane.

Transforming growth factor-beta1 down-regulation of major histocompatibility complex class I in thyrocytes: coordinate regulation of two separate elements by thyroid-specific as well as ubiquitous transcription factors

Transforming growth factor (TGF)-beta1-decreased major histocompatibility complex (MHC) class I gene expression in thyrocytes is transcriptional; it involves trans factors and cis elements important for hormone- as well as iodide-regulated thyroid growth and function. Thus, in rat FRTL-5 thyrocytes, TGF-beta1 regulates two elements within -203 bp of the transcription start site of the MHC class I 5'-flanking region: Enhancer A, -180 to -170 bp, and a downstream regulatory element (DRE), -127 to -90 bp, that contains a cAMP response element (CRE)-like sequence. TGF-beta1 reduces the interaction of a NF-kappaB p50/fra-2 heterodimer (MOD-1) with Enhancer A while increasing its interaction with a NF-kappaB p50/p65 heterodimer. Both reduced MOD-1 and increased p50/p65 suppresses class I expression. Decreased MOD-1 and increased p50/p65 have been separately associated with the ability of autoregulatory (high) concentrations of iodide to suppress thyrocyte growth and function, as well as MHC class I expression. TGF-beta1 has two effects on the downstream regulatory element (DRE). It increases DRE binding of a ubiquitously expressed Y-box protein, termed TSEP-1 (TSHR suppressor element binding protein-1) in rat thyroid cells; TSEP-1 has been shown separately to be an important suppressor of the TSH receptor (TSHR) in addition to MHC class I and class II expression. It also decreases the binding of a thyroid-specific trans factor, thyroid transcription factor-1 (TTF-1), to the DRE, reflecting the ability of TGF-beta1 to decrease TTF-1 RNA levels. TGF-beta1-decreased TTF-1 expression accounts in part for TGF-beta1-decreased thyroid growth and function, since decreased TTF-1 has been shown to decrease thyroglobulin, thyroperoxidase, sodium iodide symporter, and TSHR gene expression, coincident with decreased MHC class I. Finally, we show that TGF-beta1 increases c-jun RNA levels and induces the formation of new complexes involving c-jun, fra-2, ATF-1, and c-fos, which react with Enhancer A and the DRE. TGF-beta1 effects on c-jun may be a pivotal fulcrum in the hitherto unrecognized coordinate regulation of Enhancer A and the DRE.

Effects of modulating TGF-beta 1 on immune responses to mycobacterial infection in guinea pigs

SETTING

TGF-beta 1 has been implicated as an important mediator of immuno-suppression in clinical tuberculosis.

OBJECTIVE

The objective was to determine the role of TGF-beta 1 in experimental pulmonary tuberculosis in the guinea pig.

DESIGN

Groups of guinea pigs, maintained on either a low protein (LP) diet or an isocaloric high protein (HP) diet, were challenged via the respiratory route with virulent Mycobacterium tuberculosis H37Rv. Ten days post-infection, guinea pigs were given daily intraperitoneal injections of recombinant human TGF-beta 1 (rhTGF-beta 1 tau for 10 consecutive days). Following the treatment, guinea pigs were euthanized, and PPD-induced proliferation of peripheral blood mononuclear cells (PBMCs) was assessed and disease resistance measured by recovery of mycobacteria from the lungs and spleens. In a second set of experiments, groups of HP and LP guinea pigs were vaccinated with attenuated M. tuberculosis H37Ra. Six weeks later, the effects of rhTGF-beta 1 on lymphoproliferation and cytokine production were determined.

RESULTS

Protein deficiency significantly impaired host anti-tuberculosis resistance, as expected. Treatment with rhTGF-beta 1 significantly increased mycobacterial loads in the tissues of guinea pigs and decreased the PPD-induced proliferation of PBMCs from both LP and HP guinea pigs. PPD-driven lymphoproliferation, TNF-alpha and IFN production were significantly suppressed in vaccinated, protein-deficient guinea pigs, and rhTGF-beta 1 further inhibited lymphoproliferation and cytokine production.

CONCLUSION

Both in vivo and in vitro results indicate that TGF-beta 1 exerts immunosuppressive activity and exacerbates the progression of experimental pulmonary tuberculosis in both normally nourished and protein-deficient guinea pigs.

Induction of transforming growth factor-beta 1 production in human cells by herpes simplex virus

Transforming growth factor-beta (TGF-beta) is a cytokine of particular interest in human retrovirus infections because it can abrogate antigen-specific cellular activation. Although TGF-beta production has been observed in HIV infections, there is no evidence that herpes simplex virus (HSV)-stimulated human cells produce this cytokine. Here we present evidence, for the first time, that in vitro infection of human mononuclear cells with HSV type 1 (HSV-1) induced the release of TGF-beta1 protein. The production of this cytokine was time dependent and was found highly significant (p < 0.001) after 48 h. In addition, we observed that the secretion of TGF-beta1 was dependent on the concentration of human cells. It was found that virus needs to replicate in human cells for the production of TGF-beta1, as UV-inactivated virus did not induce significant production of cytokine protein. Interestingly, increased HSV-1-induced TGF-beta1 production in cultures containing antiinterleukin (IL)-12 or antiinterferon (IFN)-gamma antibodies was observed, whereas an irrelevant antibody had no effect on the production of this cytokine. Taken together, these findings indicate that human cells synthetize TGF-beta1 in response to HSV-1 and at the same time suggest that HSV-1-induced TGF-beta1 production may be one of the mechanisms by which HSV can at least partly evade activation of the host immune system.

Wound healing after photorefractive keratectomy

For more than 15 years, the excimer laser has been used as a surgical instrument on the cornea. Photorefractive keratectomy (PRK) followed radial keratotomy as researchers sought a more precise technique. In PRK, precision turned out to depend on surgical technique as well as the wound-healing process, with the 2 factors interdependent. The PRK technique has evolved toward a large diameter, flat ablation curvatures, and an even surface. The role of such factors as cytokines and interleukins has become more clear in the past 10 years. However, understanding the wound-healing process becomes more complicated with increasing know edge. Learning the contributing factors and performing trials with new drugs and antibodies to modulate wound healing have shown positive results on the experimental level. Patient selection based on the concentration of epidermal growth factor in tears may be another way to increase PRK s precision. The PRK technique has taught much about wound healing. For the technique to be competitive, increased precision, particularly in eyes with high myopia, is needed. Two other factors are imperative: controlling postoperative pain and decreasing visual rehabilitation time.

TGF-beta influences the life and death decisions of T lymphocytes

TGF-beta is a powerful mediator of immune cell phenotype and function. In TGF-beta1 homozygous null mice, aberrant regulation of the immune response culminates in lethal cardiopulmonary inflammation. In dissecting the underlying mechanisms leading to the attack of self, a role for TGF-beta1 in controlling apoptosis and T cell selection patterns was uncovered. Increased levels of apoptosis and TCR mediated cell death disrupted normal negative and positive T cell selection in the thymus. Moreover, in peripheral T cell populations, increased T lymphocyte death was associated with increased expression of apoptosis-inducing receptors. Persistent activation of T cells engendered unchecked apoptosis which, rather than reducing, further exacerbated, tissue inflammation due to the absence of TGF-beta1. TGF-beta, normally generated by macrophages during clearance of apoptotic cells contributes to dampening of inflammatory sequelae associated with phagocytosis. Collectively, these data demonstrate a pivotal role for TGF-beta in multiple stages of T cell apoptosis, selection, activation and clearance.

Immunology of avian influenza virus: a review

Avian influenza virus can cause serious disease in a wide variety of birds and mammals, but its natural host range is in wild ducks, gulls, and shorebirds. Infections in poultry can be inapparent or cause respiratory disease, decreases in production, or a rapidly fatal systemic disease known as highly pathogenic avian influenza (HPAI). For the protection of poultry, neutralizing antibody to the hemagglutinin and neuraminidase proteins provide the primary protection against disease. A variety of vaccines elicit neutralizing antibody, including killed whole virus vaccines and fowl-pox recombinant vaccines. Antigenic drift of influenza viruses appears to be less important in causing vaccine failures in poultry as compared to humans. The cytotoxic T lymphocyte response can reduce viral shedding in mildly pathogenic avian influenza viruses, but provides questionable protection against HPAI. Influenza viruses can directly affect the immune response of infected birds, and the role of the Mx gene, interferons, and other cytokines in protection from disease remains unknown.

Ligation of the T cell receptor complex results in phosphorylation of Smad2 in T lymphocytes

TGF-beta modulates immune responses by regulating T cell function. The Smad family of proteins has been recently shown to transduce signals for the TGF-beta superfamily and Smad2 mediates TGF-beta signaling. Here, we showed that TGF-beta phosphorylated Smad2 and induced interaction between Smad2 and Smad4 in primary T cells and the Jurkat T cell line. Interestingly, ligation of the T cell receptor (TCR)/CD3 complex with anti-CD3 mAb also phosphorylated Smad2, but failed to induce interaction between Smad2 and Smad4 in the Jurkat T cell line. Phosphorylation of Smad2 via the TCR/CD3 complex was not abrogated by treatment with neutralizing antibody against TGF-beta. Furthermore, PD98059, a MEK inhibitor, suppressed Smad2 phosphorylation by stimulation with anti-CD3 mAb in Jurkat T cell line. These findings indicated that not only TGF-beta but also stimulation via the TCR/CD3 complex phosphorylated Smad2 through mitogen-activated protein (MAP) kinase cascades, suggesting that Smad2 may function in both TGF-beta- and TCR/CD3 complex-mediated signaling pathways in T cells.

Transforming growth factor-beta is involved in the pathogenesis of dialysis-related amyloidosis

BACKGROUND

Advanced glycation end product-modified beta2-microglobulin (AGE-beta2m) is an important component of dialysis-related amyloidosis (DRA). Its presence induces monocyte chemotaxis and the release of the proinflammatory cytokines through macrophage activation. Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that also has chemotactic activity for monocytes at very low (0.1 to 10 pg/mL) concentrations and inhibits proinflammatory cytokine production of macrophages. In this study, we investigated the role of TGF-beta in the pathogenesis of DRA.

METHODS

We performed an immunohistochemical study of DRA tissues (8 cases) to confirm the existence of TGF-betas and their receptors; we also performed a chemotaxis assay of human monocytes as well as enzyme-linked immunosorbent assay (ELISA) of TGF-beta1, tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-1 receptor antagonist (IL-1Ra) in the supernatant of human monocyte-derived macrophage cell culture under varying conditions of incubation with TGF-beta1, AGE-beta2m, and TGF-beta1 antibody additions.

RESULTS

There was positive staining for TGF-betas (types 1, 2, and 3) and their receptors (types I, II, and III) in infiltrated macrophages (CD68+), synovial lining cell, as well as vascular walls around amyloid deposition. AGE-beta2m also induced TGF-beta1 production by macrophages in a dose-dependent manner (410 +/- 80 pg/mL at 12.5 microg/mL, 621 +/- 62 pg/mL at 25 microg/mL, and 776 +/- 62 pg/mL at 50 microg/mL of AGE-beta2m). AGE-beta2m induced significant TNF-alpha and IL-1Ra production by macrophage. The addition of exogenous TGF-beta1 (0.1 to 10 ng/mL) decreased AGE-beta2m-induced TNF-alpha production and increased IL-1Ra production in a dose-dependent fashion. IL-1beta production was not effected by any experimental conditions. In chemotaxis assay, anti-TGF-beta1 antibody (0.1 to 10 microg/mL) attenuated AGE-beta2m-induced monocyte chemotaxis.

CONCLUSIONS

These results provide the first evidence to our knowledge for the presence of TGF-beta in DRA tissue, as well as the stimulatory action of AGE-beta2m on tissue macrophages. In turn, TGF-beta suppresses the proinflammatory activation of macrophages, suggesting a dual role for TGF-beta in the inflammatory process of DRA. These observations may provide a pathophysiologic link between TGF-beta and DRA.

Bovine tuberculosis: immune responses in the peripheral blood and at the site of active disease

This report describes a comparison of immune responses in the peripheral blood and at the site of active disease in cattle 20 weeks after experimental infection with Mycobacterium bovis. Lymphocyte proliferation, and the production of interferon-gamma (IFN-gamma) and interleukin (IL)-2 were measured in response to tuberculin and a number of mycobacterial antigens, including ESAT-6, MPB64, MPB70, MPB83, hsp 16.1, hsp 65, hsp 70 and the 38 000 MW lipoprotein antigen. The level of transforming growth factor-beta (TGF-beta) was measured following stimulation of cells with tuberculin. Our results suggest little difference in the responses of peripheral blood and lymph node cells to most of the antigens used. However, tuberculin purified protein derivative (PPD) and ESAT-6 elicited stronger responses in the peripheral blood compared with lymph node cells. Investigation of the responding T-cell subpopulations in the peripheral blood showed that both CD4+ and, to a lesser extent, gammadelta T-cell receptor-positive (TCR+) T cells contributed to these responses. This is the first report to compare peripheral and local immune responses in bovine tuberculosis. Unlike cases of human tuberculosis where immune activity at the site of disease and anergy in the peripheral blood have been reported, our results suggest that for bovine tuberculosis immune responses occurring in the peripheral blood reflect those at the site of disease.

Impact of burn injury on hepatic TGF-beta1 expression and plasma TGF-beta1 levels

BACKGROUND

The liver plays a critical regulatory role in the acute inflammatory response to injury, although the mechanisms of this regulation are not well understood. transforming growth factor-beta1 (TGF-beta1) is induced after burn injury and may contribute to an inhibitory or fatal effect on hepatocytes. We investigated the association over time between plasma concentration of TGF-beta1, expression of TGF-beta1 m-RNA in liver tissue, and histologic analysis of liver apoptosis after burn injury.

METHODS

Male BALB/c mice were anesthetized and randomized to receive 0% (sham), moderate (approximately 25%) (M), or large (approximately 50%) (L) body surface area full-thickness contact burn, followed by resuscitation and analgesia. Animals were killed over a time course from 15 minutes to 24 hours after burn injury, and liver tissue and peripheral blood were collected. Plasma levels of TGF-beta1 (nanograms per milliliter) were measured by enzyme-linked immunosorbent assay. TGF-beta1 m-RNA was extracted from liver and measured by reverse transcription-polymerase chain reaction. Histology of liver apoptosis was examined after fixation and staining with TdT-mediated dUTP nick-end labeling (TUNEL) method.

RESULTS

The plasma concentration of TGF-beta in burn group L was significantly increased at 4 hours after burn when compared with sham and M burn groups. This rise in plasma TGF-beta1 was preceded by an increase in hepatic TGF-beta1 m-RNA expression at 30 minutes, 1, 2, and 4 hours after burn in the L group. Histologic analysis found greater hepatocyte death in the L group than in the M group at 8 hours after burn.

CONCLUSION

The levels of induced TGF-beta1 and TGF-beta1 m-RNA after L burn injury are higher and peak earlier than after M burn injury. Elevated TGF-beta1 may be associated with cell death in hepatocytes. The TGF-beta1 rise may be associated with hepatocyte injury and systemic response to massive burn.

Transforming growth factor-beta1 regulates basement membrane formation by alveolar epithelial cells in vitro

Immortalized alveolar type II epithelial (SV40-T2) cells formed a continuous, thin lamina densa when they were cultured on collagen fibrils with the supplement of 1.0 ng/ml TGF-beta1. Corresponding to lamina densa formation, immunohistochemical analysis of laminin, type IV collagen, perlecan, and entactin (nidogen) indicated integration of these components in a linear array beneath the SV40-T2 cells. Synthesis of these basement membrane constituents was significantly enhanced by TGF-beta1 in a dose-dependent manner. On the other hand, TGF-beta1 did not affect the synthesis of extracellular matrix-regulatory enzymes and their inhibitors, such as type II transglutaminase, matrix metalloproteinase-2, plasminogen activator inhibitor-1, or tissue inhibitor of matrix metalloproteinase-1. These results indicate that basement membrane formation in the presence of 1.0 ng/ml TGF-beta1 is attributable to enhanced synthesis of basement membrane constituents. However, formation of a continuous basement membrane was inhibited at a TGF-beta1 concentration of 5.0 ng/ml. Synthesis of the basement membrane constituents was further enhanced at this concentration and the extracellular matrix-regulatory enzymes remained unchanged. The deposits of cellular fibronectin and type I collagen beneath SV40-T2 cells were significantly augmented. Thus excessive production of interstitial extracellular matrix components appears to obstruct the integration of basement membrane constituents into a continuous architecture. These results indicate that the basement membrane formation by SV40-T2 cells is achieved at the optimal TGF-beta1 concentration.

Manipulation of TGF-beta to control autoimmune and chronic inflammatory diseases

Defining the mechanisms whereby transforming growth factor-beta (TGF-beta) controls physiologic inflammation and the immune response and how it contributes to pathology when it is dysregulated is critical to our ability to manipulate the levels and activity of this potent cytokine for therapeutic benefit. In keeping with its dichotomous nature, recent evidence suggests that overproduction and/or activation contribute to persistent inflammation and that antagonists of TGF-beta delivered locally can break the cycle of leukocyte recruitment and fibrotic sequelae. On the other hand, systemic routing of TGF-beta can also inhibit inflammatory pathogenesis by multiple mechanisms as exemplified by systemic injections of the protein and by recent gene transfer studies. In addition, enhanced levels of circulating endogenous TGF-beta appear to be an instrument of suppression during the development of oral tolerance, cyclosporin treatment, and following administration of retinoic acid. Although treatment of autoimmune and chronic inflammatory diseases is an important goal, the multiplicity of actions of TGF-beta and the nearly ubiquitous expression of TGF-beta and its receptors dictate a cautious approach to the use of this powerful cytokine as a therapeutic agent.

Bidirectional regulation of macrophage function by TGF-beta

The dual role of transforming growth factor-beta (TGF-beta) in modulating macrophage function is an important concept gaining increasing recognition. In addition to its role as a 'macrophage-deactivating' agent, TGF-beta functions as a monocyte activator, inducing cytoke production and mediating host defence. These functions are context-dependent, modulated by the differentiation state of the cell, the local cytokine environment, and the local levels of TGF-beta in itself. In general, during the initial stages of inflammation, TGF-beta locally acts as a proinflammatory agent by recruiting and activating resting monocytes. As these cells differentiate specific immunosuppressive actions of TGF-beta predominate, leading to resolution of the inflammatory response. Increasing our understanding of the bidirectional regulation of macrophage function will facilitate prediction of the ultimate outcome of modulating TGF-beta levels in vivo.

Interaction of Mycobacterium tuberculosis-induced transforming growth factor beta1 and interleukin-10

Mycobacterium tuberculosis is associated with the activation of cytokine circuits both at sites of active tuberculosis in vivo and in cultures of mononuclear cells stimulated by M. tuberculosis or its components in vitro. Interactive stimulatory and/or inhibitory pathways are established between cytokines, which may result in potentiation or attenuation of the effects of each molecule on T-cell responses. Here we examined the interaction of transforming growth factor beta1 (TGF-beta1) and interleukin-10 (IL-10) in purified protein derivative (PPD)-stimulated human mononuclear cell cultures in vitro. TGF-beta1 induced monocyte IL-10 (but not tumor necrosis factor alpha) production (by 70-fold, P < 0.02) and mRNA expression in the absence but not in the presence of PPD. Both exogenous recombinant (r) IL-10 and rTGF-beta1 independently suppressed the production of PPD-induced gamma interferon (IFN-gamma) in mononuclear cells from PPD skin test-positive individuals. Synergistic suppression of IFN-gamma in cultures containing both rTGF-beta1 and rIL-10 was only seen when the responder cell population were peripheral blood mononuclear cells (PBMC) and not monocyte-depleted mononuclear cells and when PBMC were pretreated with rTGF-beta1 but not with rIL-10. Suppression of PPD-induced IFN-gamma in PBMC containing both rTGF-beta1 (1 ng/ml) and rIL-10 (100 pg/ml) was 1.5-fold higher (P < 0.05) than cultures containing TGF-beta1 alone and 5.7-fold higher (P < 0.004) than cultures containing IL-10 alone. Also, neutralization of endogenous TGF-beta1 and IL-10 together enhanced PPD-induced IFN-gamma in PBMC in a synergistic manner. Thus, TGF-beta1 and IL-10 together potentiate the downmodulatory effect on M. tuberculosis-induced T-cell production of IFN-gamma, and TGF-beta1 alone enhances IL-10 production. At sites of active M. tuberculosis infection, these interactions may be conducive to the suppression of mononuclear cell functions.

β2-Microglobulin-Deficient Background Ameliorates Lethal Phenotype of the TGF-β1 Null Mouse

TGF-β1 null (TGF-β1−/−) mice die at 3–4 wk of age and show an autoimmune inflammatory phenotype associated with enhanced expression of both class I and II MHC molecules. To determine the role of MHC class I Ags in the autoimmune manifestations and the inflammation observed in TGF-β1−/− mice, we generated TGF-β1−/− mice in the genetic background of β2-microglobulin deficiency (β2M−/−). TGF-β1−/−;β2M−/− mice had improved survival compared with TGF-β1−/− mice. Histopathological examination showed less severe inflammation, especially in the heart, where Mac-2 reactive macrophages were significantly decreased as compared with TGF-β1−/− mice. In vivo depletion of CD8+ T cells in TGF-β1−/− mice confirmed suppression of inflammation and reduction in the severity of the wasting syndrome. MHC class II mRNA expression in TGF-β1−/−;β2M−/− mice was also lower than that in TGF-β1−/− mice, suggesting reduced systemic inflammation. Autoimmune response as judged by serum Ab titers to ssDNA and 16/6 Id and by immune complex deposits in kidney was reduced in TGF-β1−/−;β2M−/− mice, when compared with that in TGF-β1−/− mice. Our data thus indicate that MHC class I molecules influence the development of the autoimmunity and the inflammation seen in TGF-β1−/− mice and CD8+ T cells may have a contribution to the inflammation in TGF-β1−/− mice.

Inhibition of Bacterial Cell Wall-Induced Leukocyte Recruitment and Hepatic Granuloma Formation by TGF-β Gene Transfer

Intraperitoneal injection of streptococcal cell walls (SCW) into Lewis rats results in dissemination of SCW to the liver, spleen, bone marrow, and peripheral joints. The uptake of SCW by Kupffer cells in the liver initiates a chain of events largely mediated by T lymphocytes and macrophages. Local synthesis and secretion of cytokines and growth factors in response to the persistent SCW lead to the evolution and maintenance of a chronic T cell-dependent granulomatous response and result in granuloma formation and irreversible hepatic fibrosis. In an attempt to impede the development of the chronic granulomatous lesions in the liver, we injected a plasmid DNA encoding TGF-β1 i.m. to the SCW animals to determine the effect of TGF-β1 gene transfer on the course of liver inflammation and fibrosis. A single injection of plasmid DNA encoding TGF-β1 resulted in virtual abolition of the development of the SCW-induced hepatic granuloma formation and matrix expansion. TGF-β1 DNA not only reduced key proinflammatory cytokines including TNF-α, IL-1β, IFN-γ, and IL-18, but also inhibited both CXC and CC chemokine production, thereby blocking inflammatory cell recruitment and accumulation in the liver. Moreover, TGF-β1 gene delivery inhibited its own expression in the liver tissue, which is otherwise up-regulated in SCW-injected animals. Our study suggests that TGF-β1 gene transfer suppresses hepatic granuloma formation by blocking the recruitment of inflammatory cells to the liver, and thus may provide a new approach to the control of hepatic granulomatous and fibrotic diseases.

Characterization of the rat, mouse, and human genes of growth/differentiation factor-15/macrophage inhibiting cytokine-1 (GDF-15/MIC-1)

We have isolated the rat, mouse and human genes of a distant member of the TGF-beta superfamily, growth/differentiation factor-15/macrophage inhibiting cytokine-1 (GDF-15/MIC-1) by screening of genomic libraries. All three genes are composed of two exons, and contain one single intron that interrupts the coding sequences at identical positions within the prepro-domain of the corresponding proteins. The predicted proteins contain the structural hallmarks of members of the TGF-beta superfamily, including the seven conserved carboxy-terminal cysteine residues that form the cystine knot. The orthologous molecules show the lowest sequence conservation of all members of the TGF-beta superfamily. RT-PCR reveals an abundant expression of GDF-15/MIC-1 mRNA in numerous embryonic and adult organs and tissues. Promoter analysis of the rat promoter indicates the presence of multiple regulatory elements, including a TATA-like sequence as well as several SP1, AP-1 and AP-2 sites. Deletion analysis suggests that a 350 bp region upstream of the start of the open reading frame appears to be the most important for regulation of transcription.

Effects of TGFbeta2 on collagen synthesis in cultured normal and wounded fetal mouse palates

OBJECTIVE

It has been demonstrated in a number of models that fetal wounds heal with little or no scar. Since collagen is an integral part of the extracellular matrix in adult scar formation, we studied the synthesis and localization of collagen in an in vitro mouse palate model for fetal wound healing.

METHODS

Palates, dissected from fetal mice at 15, 16, and 17 days of gestation and from newborn mice, were cultured in medium containing serum (for 8 hours); this was followed by culture in serum-free medium (for 12 hours). One-half of the samples from each age group were wounded in the midline. All samples were placed in serum-free medium containing 20 microCi/mL 3H-proline for 8 hours. In addition, palates from 15-day gestation and from newborn mice were also incubated with transforming growth factor TGF-beta2 (10 ng/mL). Palates were washed with saline, homogenized, and radioactivity was counted. Proline uptake was calculated for each sample as counts per milligram of protein and was subjected to statistical analysis (three-way analysis of variance). Samples of the homogenate were subjected to sodium dodecyl sulfate-gel electrophoresis and Western blotting in order to determine the types of collagen that were synthesized. Immunohistochemical localization of collagen types I, III, and VI was carried out on paraffin-embedded samples from each group.

RESULTS

There were no significant differences in proline uptake between wounded mouse palates and nonwounded mouse palates at any age, and there was no histological evidence of regeneration of the palate at the site of the wound. Proline uptake was significantly greater in untreated wounded palates at 15 days' gestation than it was in newborns. After treatment with TGF-beta2, proline uptake was significantly greater in both wounded and nonwounded palates in the newborn group and had no effect on collagen synthesis in palates from 15-day gestation animals. Collagen types I and III were localized in histological specimens using immunohistochemistry and on nitrocellulose using Western blotting. No type VI collagen was demonstrated by Western blotting, but it was localized around blood vessels and on basement membranes using immunohistochemistry.

CONCLUSION

Treatment with TGF-beta2 significantly increased collagen synthesis, as assessed by 3H-proline uptake, in cultured palates from newborn mice as compared with palates from untreated newborn mice and from both treated and untreated palates of 15-day gestation mice. These data suggest a differential response to TGF-beta2 by mouse palates as a function of fetal development.

Photopheresis: clinical applications and mechanism of action

Photopheresis is a leukapheresis-based therapy that utilizes 8-methoxypsoralen and ultraviolet A irradiation. Photopheresis is currently available at approximately 150 medical centers worldwide. Recent evidence suggests that this therapy used as a single agent may significantly prolong life, as well as induce a 50%-75% response rate among individuals with advanced cutaneous T cell lymphoma (CTCL). Furthermore, a 20%-25% complete response rate with photopheresis alone, or in combination with other biologic response modifiers, has been obtained at our institution among patients with Sezary syndrome. These complete responses have been characterized by the complete disappearance of morphologically atypical cells from the skin and blood. The use of sensitive molecular techniques has also confirmed the sustained disappearance of the malignant T cell clone from the blood of patients with complete responses. In addition to the treatment of CTCL, numerous reports indicate that photopheresis is a potent agent in the therapy of acute allograft rejection among cardiac, lung, and renal transplant recipients. Chronic graft versus host disease also appears to be quite responsive to photopheresis therapy. Likewise, there may also be a potential role for photopheresis in the therapy of certain autoimmune diseases that are poorly responsive to conventional therapy. The immunologic basis for the responses of patients with these conditions is likely due to the induction of anticlonotypic immunity directed against pathogenic clones of T lymphocytes. Treatment-induced apoptotic death of pathogenic T cells and activation of antigen presenting cells are postulated to have important effects in this therapeutic process.

Evidence for apoptosis induction in myofibroblasts during palatal mucoperiosteal repair

Apoptosis is thought to be a requisite event for maintaining kinetic homeostasis within continually renewing tissues such as the oral mucosa and skin. However, no systematic study of the apoptotic process in fibroblasts in the oral mucosa following injury has been performed. In this study, we have assessed the expression of transforming growth factor-beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF), which are among the most important modulators of wound repair, during wound healing following mucoperiosteal injury in the rat palate. In addition, we have investigated fibroblast differentiation and apoptosis by immunohistochemical analysis for alpha-smooth-muscle (alpha-SM) actin or DNA strand breaks, respectively, to clarify the mechanisms of the wound healing process. TGF-beta1-positive cells were noted in the subepithelium from Day 2 to Day 14 after injury, by which time the wounds were completely reepithelialized. Strong expression of bFGF was observed, mainly in macrophages and monocytes at the injured site, from Day 10 to Day 14 after injury. TGF-beta1 and bFGF-immunostaining was significantly lower during the later phase of wound healing. In addition, the number of myofibroblasts expressing alpha-SM actin increased (peak at Day 14), and thereafter gradually decreased. In parallel, the apoptosis in myofibroblasts was prominent on Day 14. These results suggest that TGF-beta1 and bFGF may be potential stimulators of apoptosis in myofibroblasts after re-epithelialization in the palatal wound healing process. The regulation of apoptotic phenomena during wound healing may be important in scar establishment and development of pathological scarring.

Transforming growth factor-beta impairs postburn immunoglobulin production by limiting B-cell proliferation, but not cellular synthesis

BACKGROUND

Transforming growth factor-beta (TGF-beta) has been shown to be an inhibitor of immunoglobulin (Ig) synthesis and may contribute to decreased Ig synthesis after burn injury. This study investigated the relationship between TGF-beta and Ig synthesis after burn injury.

METHODS

Twenty-four BALB/c mice received either a 30% body surface area full-thickness contact burn or no burn. Splenocytes were isolated 8 days after burn and were cultured with 0, 0.05 or 0.5 ng/mL TGF-beta. After culture, total IgG and total IgM were measured by enzyme-linked immunosorbent assay. The number of IgM-secreting cells per 10(5) cells was measured by enzyme-linked immunoabsorbent spot forming assay. Total IgM per IgM-secreting cell (pg/cell) was calculated.

RESULTS

Total IgG, IgM, IgM-secreting cells, and B-cell number after culture were decreased by burn injury, and the decrease was exacerbated by the presence of TGF-beta. The total IgM per IgM-secreting cells, however, was significantly increased by TGF-beta at 0.5 ng/mL.

CONCLUSION

These data demonstrates that TGF-beta does not specifically impair IgM secretion by committed IgM B cells but appears to decrease B-cell proliferation or clonal expansion.

Effects of filtration and gamma radiation on the accumulation of RANTES and transforming growth factor-beta1 in apheresis platelet concentrates during storage

BACKGROUND

Platelet-derived biologic response modifiers (BRMs) including RANTES and transforming growth factor (TGF)-beta1 accumulate in platelet components during storage because of platelet activation, and they may play a causative role in nonhemolytic febrile transfusion reactions. The majority of PCs with high unit values are provided by single donor apheresis in Japan.

STUDY DESIGN AND METHODS

RANTES and TGF-beta1 levels in platelet units prepared from single-donor apheresis platelet concentrates (apheresis PCs) and units from whole blood (buffy coat PCs) were investigated. The effects of prestorage and poststorage filtration and gamma radiation on the levels of RANTES and TGF-beta1 in the supernatant of apheresis PCs during storage were also examined.

RESULTS

The levels of RANTES and TGF-beta1 increased during storage from Day 0 to Day 5. The levels of RANTES and of TGF-beta1 correlated with the platelet concentration (p<0.01), but not with the residual white cell concentration in apheresis PCs that were not white cell reduced by filtration (p>0.05). In addition, there was a correlation between RANTES and TGF-beta1 levels (p<0.01). In white cell-reduced apheresis PCs using negatively charged filters as well as in gamma-radiated apheresis PCs, the levels of these two BRMs-did not differ at any storage time from those of untreated apheresis PCs. Filtration of apheresis PCs with negatively charged filters after 3 days of storage significantly (p<0.05) reduced the levels of RANTES, but not of TGF-beta1. There was no reduction in the levels of RANTES and TGF-beta1 levels by positively charged filters. The RANTES levels in buffy coat PCs were slightly higher than but not significantly different from those of apheresis PCs during storage, except for the level on Day 1. There were no differences in the TGF-beta1 levels in apheresis and buffy coat PCs during storage.

CONCLUSION

Prestorage filtration and gamma radiation had neither preventive effects on the accumulation of RANTES and TGF-beta1 nor adverse effects on platelet activation. Negatively charged filters might be useful for the reducing the levels of RANTES in stored apheresis PCs.

Ex vivo transfection of transforming growth factor-beta1 gene to pulmonary artery segments in lung grafts

OBJECTIVE

Proximal pulmonary artery segment transfection may provide beneficial downstream effects on the whole-lung graft. In this study, transforming growth factor-beta1 was transfected to proximal pulmonary artery segments, and the efficacy of transforming growth factor-beta1 transfection was examined in ischemia-reperfusion injury and acute rejection models of rat lung transplantation.

METHODS

In the ischemia-reperfusion injury model, orthotopic left lung transplantation was performed in F344 rats. In group I, the PPAS was isolated and injected with saline solution. In 2 other groups, lipid67:DOPE:sense (group II) or antisense transforming growth factor-beta1pDNA construct (group III) was injected instead of saline solution. After cold preservation at 4 degrees C for 18 hours, lung grafts were implanted. Graft function was assessed 24 hours later. In the acute rejection model, donor lung grafts were harvested. Proximal pulmonary artery segments were injected with saline solution (group I) or sense (group II) or antisense lipid gene construct (group III) and then implanted. Graft function was assessed on postoperative day 5.

RESULTS

In the ischemia-reperfusion injury study, there were no significant differences in oxygenation, wet-to-dry weight ratios, graft myeloperoxidase activity, or transforming growth factor-beta1 levels in platelet-poor serum or proximal pulmonary artery segment homogenates. In the acute rejection study, oxygenation was significantly improved in group II receiving transforming growth factor-beta1 (group II vs I and III, 136.0 +/- 32.5 vs 54.0 +/- 9.6 mm Hg and 53.8 +/- 14.8 mm Hg; P =.016 and.016). There were no significant pathologic differences. Transforming growth factor-beta1 concentrations from proximal pulmonary artery segment homogenates in group II were significantly higher compared with controls.

CONCLUSIONS

Ex vivo transfection of transforming growth factor-beta1 to proximal pulmonary artery segments did not affect reperfusion injury of lung isografts. In acute rejection, however, ex vivo transfection of transforming growth factor-beta 1 to proximal pulmonary artery segments improved allograft function. This suggests that transfection to proximal pulmonary artery segments exerts beneficial downstream effects on the whole-lung allograft.

Expression of transforming growth factor beta1 and its receptors in normal human urothelium and human transitional cell carcinomas

Previous studies indicated that transforming growth factor beta1 (TGFbeta1) is expressed by normal urothelial cells and exerts regulatory autocrine functions in urothelial maintenance and wound healing. However, little is known about the expression patterns of TGFbeta1 and its receptors in bladder tumors. Therefore, we studied the protein and mRNA localization of TGFbeta1 and TGFbeta receptor types I and II (TGFbetaRI and TGFbetaRII) in normal human urothelium and transitional cell carcinomas (TCCs) of different grades and stages. Expression of TGFbeta1 and its receptors was examined by immunocytochemistry and mRNA in situ hybridization in normal urothelium and TCCs using a semiquantitative method. By immunocytochemistry, the expression of TGFbeta1 and TGFbetaRII was higher in superficial and basal cell layers of normal urothelium than in the intermediate layer. A similar localization was seen in superficial TCCs. TGFbetaRI was mainly present in basal and intermediate cell layers of normal urothelium and superficial TCCs. In contrast, in muscle invasive TCCs, all tumor cells stained intensely for all three proteins. No correlation was found between immunostaining and TCC grade. In situ hybridization pointed out that all cell layers in normal urothelium exhibit similar TGFbeta1 mRNA levels. Elevated TGFbeta1 mRNA levels were noted in TCCs irrespective of grade or stage. In conclusion, these data indicate that in normal urothelium TGFbeta1, TGFbetaRI, and TGFbetaRII expression depend on maturation and differentiation. This pattern is particularly lost in muscle invasive TCCs, in which the expression of the three proteins is enhanced. These data suggest autocrine TGFbeta1 mechanisms in human TCC cells that may be more pronounced in muscle invasive TCC cells.

Increased levels of transforming growth factor beta 1 and basic fibroblast growth factor in patients on CAPD: a study during non-infected steady state and peritonitis

Long-term influence of continuous ambulatory peritoneal dialysis (CAPD) on concentrations of transforming growth factor beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF) in the peritoneal effluent, and the effect of peritonitis on these cytokines were investigated. TGF-beta1 and bFGF were assayed in effluent samples from dialysate bags collected during the initial week of treatment with CAPD and at 5 months. To determine the effect of peritonitis, dialysate bags were collected on admission to the hospital and on days 3 and 10 and also during non-infected steady state. Serum was drawn prior to infection and on days 1 and 10. TGF-beta1 increased more than threefold during the longitudinal follow-up period, median concentrations of 35 pg/ml to 106 pg/ml (P<0.05). No change in bFGF was seen during this initial 5 months. TGF-beta1 was increased on the first day of peritonitis (median concentration 169 pg/ml) and reached its maximum on day 3 of infection, (median concentration 216 pg/ml) (P<0.05 vs non-infected state, median concentration 39 pg/ml). Basic FGF reached a maximum on day three of infection (median concentration 7.7 pg/ml; P=0.01 vs non-infected state) and then slowly declined. In conclusion, TGF-beta1 is influenced by CAPD treatment per se, and together with bFGF is increased during peritonitis, indicating its importance in the peritoneum and its potential involvement in the development of tissue fibrosis and eventually ultrafiltration failure.

The modulating effects of proinflammatory cytokines interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha), and immunoregulating cytokines IL-10 and transforming growth factor-beta (TGF-beta), on anti-microbial activity of murine peritoneal macrophages against Mycobacterium avium-intracellulare complex

We assessed the roles of proinflammatory cytokines IFN-gamma and TNF-alpha, and immunoregulatory cytokines IL-10 and TGF-beta in the modulation of the anti-microbial activity of murine peritoneal macrophages against Mycobacterium avium-intracellulare complex (MAIC). First, both IFN-gamma and TNF-alpha significantly reduced the bacterial growth in macrophages, indicating that these cytokines participate in up-regulation of macrophage anti-MAIC function. Second, although MAIC-infected macrophages produced substantial amounts of IL-10 and TGF-beta, neutralization of endogenous IL-10 and TGF-beta with anti-IL-10 and anti-TGF-beta antibodies, respectively, did not affect the intracellular growth of MAIC in macrophages from mice with BcgS (MAIC-susceptible) or BcgI (MAIC-resistant) genotype, regardless of the virulence of test MAIC strains. The same result was also obtained for macrophages stimulated with IFN-gamma or TNF-alpha. Third, in MAIC-infected mice, the growth of organisms at the sites of infection (lungs and spleens) was not affected by administration of anti-IL-10 or anti-TGF-beta antibodies. These findings indicate that, in the case of mice, endogenous IL-10 and TGF-beta are essentially ineffective in down-regulating macrophage anti-MAIC functions not only in vitro but also in vivo.

Effects of the Chinese traditional medicine mao-bushi-saishin-to on therapeutic efficacy of a new benzoxazinorifamycin, KRM-1648, against Mycobacterium avium infection in mice

The Chinese traditional medicine mao-bushi-saishin-to (MBST), which has anti-inflammatory effects and has been used to treat the common cold and nasal allergy in Japan, was examined for its effects on the therapeutic activity of a new benzoxazinorifamycin, KRM-1648 (KRM), against Mycobacterium avium complex (MAC) infection in mice. In addition, we examined the effects of MBST on the anti-MAC activity of murine peritoneal macrophages (M phi s). First, MBST significantly increased the anti-MAC therapeutic activity of KRM when given to mice in combination with KRM, although MBST alone did not exhibit such effects. Second, MBST treatment of M phi s significantly enhanced the KRM-mediated killing of MAC bacteria residing in M phi s, although MBST alone did not potentiate the M phi anti-MAC activity. MBST-treated M phi s showed decreased levels of reactive nitrogen intermediate (RNI) release, suggesting that RNIs are not decisive in the expression of the anti-MAC activity of such M phi populations. MBST partially blocked the interleukin-10 (IL-10) production of MAC-infected M phi s without affecting their transforming growth factor beta (TGF-beta)-producing activity. Reverse transcription-PCR analysis of the lung tissues of MAC-infected mice at weeks 4 and 8 after infection revealed a marked increase in the levels of tumor necrosis factor alpha, gamma interferon (IFN-gamma), IL-10, and TGF-beta mRNAs. KRM treatment of infected mice tended to decrease the levels of the test cytokine mRNAs, except that it increased TGF-beta mRNA expression at week 4. MBST treatment did not affect the levels of any cytokine mRNAs at week 8, while it down-regulated cytokine mRNA expression at week 4. At week 8, treatment of mice with a combination of KRM and MBST caused a marked decrease in the levels of the test cytokines mRNAs, especially IL-10 and IFN-gamma mRNAs, although such effects were obscure at week 4. These findings suggest that down-regulation of the expression of IL-10 and TGF-beta is related to the combined therapeutic effects of KRM and MBST against MAC infection.

M6P/IGFII-receptor complexes urokinase receptor and plasminogen for activation of transforming growth factor-beta1

Transforming growth factor-beta1 (TGF-beta1) is a critical cytokine for cell proliferation and differentiation. It is secreted by many cells in a latent pro-form (LTGF-beta1) from which biologically active TGF-beta1 is released by an in vivo mechanism that is not known. Here we show that the mannose-6-phosphate/insulin-like growth factor II-receptor (M6P/IGFII-R), which binds LTGF-beta1, complexes with urokinase (plasminogen activator)-receptor (uPA-R) on the surface of human monocytes and directly binds plasminogen (Plg). Plasmin generated from Plg in the complex mediates release of TGF-beta1 when M6P/IGFII-R is associated with uPA-R. Thus, this interaction of M6P/IGFII-R and uPA-R suggests a potential mechanism for the generation of TGF-beta1 by cells.