Interaction of adenosine 3',5'-cyclic monophosphate and tumor necrosis factor-alpha on serum amyloid A3 expression in mouse granulosa cells: dependence on CCAAT-enhancing binding protein-beta isoform

TNFalpha is an inflammatory-related cytokine that has inhibitory effects on gonadotropin- and cAMP-stimulated steroidogenesis and folliculogenesis. Because ovulation is an inflammatory reaction and TNF specifically induces serum amyloid A3 (SAA3) in mouse granulosa cells, the effect of cAMP on TNF-induced SAA3 promoter activity, mRNA and protein was investigated. Granulosa cells from immature mice were cultured with TNF and/or cAMP. TNF increased SAA3 promoter activity, mRNA, and protein, which were further increased by cAMP. cAMP alone increased SAA3 promoter activity, but SAA3 mRNA and protein remained undetectable. Thus, there appeared to be different mechanisms by which TNF and cAMP regulated SAA3 expression. SAA3 promoters lacking a nuclear factor (NF)-kappaB-like site or containing its mutant were not responsive to TNF but were responsive to cAMP. Among four CCAAT-enhancing binding protein (C/EBP) sites in the SAA3 promoter, the C/EBP site nearest the NF-kappaB-like site was required for TNF-induced SAA3. The C/EBP site at -75/-67 was necessary for responsiveness to cAMP. Dominant-negative C/EBP and cAMP response element-binding protein or short interfering RNA of C/EBPbeta blocked TNF- or cAMP-induced SAA3 promoter activity. The combination of TNF and cAMP increased C/EBPbeta protein above that induced by TNF or cAMP alone. Thus, cAMP in combination with TNF specifically induced C/EBPbeta protein, leading to enhanced SAA3 expression but requiring NF-kappaB in mouse granulose cells. In addition, like TNF, SAA inhibited cAMP-induced estradiol accumulation and CYP19 levels. These data indicate SAA may play a role in events occurring during the ovulation process.

Expression of Neutral Glycosphingolipids in the Brain and Spleen of Mice Lacking TNF Receptor 1

We investigated the expression of neutral glycosphingolipids (GSLs) in the brain and spleen of mice lacking the gene for the tumor necrosis factor-alpha receptor p55 (TNFR1). Neutral GSLs of the ganglio-, globo-, and neolacto-series were determined in the tissues of homozygous (TNFR1-/-) and control heterozygous (TNFR1+/-) animals by high performance thin layer chromatography (HPTLC) overlay immunostaining with specific antibodies. The spleen of homozygous TNFR1 knockout mice lacked glucosylceramide substituted with palmitic acid, GlcCer(C16), and showed severe reduction in the expression of GlcCer(C24). In addition, gangliotetraosylceramide substituted with palmitic acid, Gg4Cer(C16), and globotetraosylceramide, Gb4Cer, were down-regulated in the TNFR1-/- spleen in comparison with the heterozygous control. The brain of both groups of animals (TNFR1-/- and TNFR1+/-) did not express detectable levels of Gg4Cer, Gb5Cer and Gb4Cer, but the brain of TNFR1 knockout mice expressed abundant globotriaosylceramide, Gb3Cer, compared to no expression in control heterozygous mice. nLcCer(C24) had slightly higher (1.4 fold) expression in the brain of TNFR1-/- mice compared with the control animals. This study provides in vivo evidence that TNF signaling via the TNFR1 is involved in the acquisition of a divergent GSL assembly in the brain, an immunologically privileged organ, and the spleen, typical secondary lymphoid organ.

Adenovirus RID complex enhances degradation of internalized tumour necrosis factor receptor 1 without affecting its rate of endocytosis

The receptor internalization and degradation (RID) complex of adenovirus plays an important role in modulating the immune response by downregulating the surface levels of tumour necrosis factor receptor 1 (TNFR1), thereby inhibiting NF-κB activation. Total cellular content of TNFR1 is also reduced in the presence of RID, which can be inhibited by treatment with lysosomotropic agents. In this report, surface biotinylation experiments revealed that, although RID and TNFR1 were able to form a complex on the cell surface, the rate of TNFR1 endocytosis was not affected by RID. However, the degradation of internalized TNFR1 was enhanced significantly in the presence of RID. Therefore, these data suggest that RID downregulates TNFR1 levels by altering the fate of internalized TNFR1 that becomes associated with RID at the plasma membrane, probably by promoting its sorting into endosomal/lysosomal degradation compartments.

Immunoprivileged status of the liver is controlled by Toll-like receptor 3 signaling

The liver is known to be a classical immunoprivileged site with a relatively high resistance against immune responses. Here we demonstrate that highly activated liver-specific effector CD8+ T cells alone were not sufficient to trigger immune destruction of the liver in mice. Only additional innate immune signals orchestrated by TLR3 provoked liver damage. While TLR3 activation did not directly alter liver-specific CD8+ T cell function, it induced IFN-alpha and TNF-alpha release. These cytokines generated expression of the chemokine CXCL9 in the liver, thereby enhancing CD8+ T cell infiltration and liver disease in mice. Thus, nonspecific activation of innate immunity can drastically enhance susceptibility to immune destruction of a solid organ.

Differential inhibition of TRAIL-mediated DR5-DISC formation by decoy receptors 1 and 2

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family that induces cancer cell death by apoptosis with some selectivity. TRAIL-induced apoptosis is mediated by the transmembrane receptors death receptor 4 (DR4) (also known as TRAIL-R1) and DR5 (TRAIL-R2). TRAIL can also bind decoy receptor 1 (DcR1) (TRAIL-R3) and DcR2 (TRAIL-R4) that fail to induce apoptosis since they lack and have a truncated cytoplasmic death domain, respectively. In addition, DcR1 and DcR2 inhibit DR4- and DR5-mediated, TRAIL-induced apoptosis and we demonstrate here that this occurs through distinct mechanisms. While DcR1 prevents the assembly of the death-inducing signaling complex (DISC) by titrating TRAIL within lipid rafts, DcR2 is corecruited with DR5 within the DISC, where it inhibits initiator caspase activation. In addition, DcR2 prevents DR4 recruitment within the DR5 DISC. The specificity of DcR1- and DcR2-mediated TRAIL inhibition reveals an additional level of complexity for the regulation of TRAIL signaling.

Expression of p14ARF, p15INK4b, p16INK4a, and DCR2 increases during prostate cancer progression

Prostate carcinoma is a hormonally driven age-related neoplasm. Cellular senescence is an age-related process where cells remain metabolically active but in a growth-arrested state at the G1 phase. p14(ARF), p15(INK4b), and p16(INK4a), which are known to regulate G1 cell cycle arrest, and the tumor necrosis factor receptor superfamily member decoy receptor 2 (DCR2), have been recently identified as senescence markers. The purpose of this study was to characterize and compare the expression of p14(ARF), p15(INK4b), p16(INK4a), and DCR2 in tissue microarrays containing cases of normal prostate, nodular hyperplasia, prostate intraepithelial neoplasia (PIN), and malignant prostate cancer tissue. We performed immunohistochemical staining for p14(ARF), p15(INK4b), p16(INK4a), and DCR2 in tissue microarray blocks containing 41 cores of normal prostate, 65 cores of nodular hyperplasia, 21 cores of PIN, 69 cores of low-grade prostate carcinoma, and 42 cores of high-grade prostate carcinoma, derived from 80 cases of prostatectomy with adenocarcinomas. We detected positive staining of p16(INK4a) in 19% of the PIN, 25% of the low-grade carcinoma, and 43% of the high-grade carcinoma specimens but none in the normal prostate and nodular hyperplasia specimens. Expression of p14(ARF) revealed very high levels of expression in normal tissues (83%), nodular hyperplasia (88%), PIN (89%), and cancer cells (100%). P15(INK4b) and DCR2 were found positive in 81 and 33% normal, 46 and 10% nodular hyperplasia, 74 and 36% PIN tissues, 87 and 89% low-grade carcinomas, and 100 and 93% high-grade carcinomas. There is an increased protein expression of senescence-associated molecular markers, indicating that cellular senescence might play a role in prostate carcinoma. Because p16(INK4a)-positive cells were detected only in premalignant lesions and carcinomas but not in normal or benign tissues, p16(INK4a) may aid in the diagnosis of PIN and prostate cancer in difficult cases.

TRAIL-R4-β: A new splice variant of TRAIL-receptor 4 lacking the cysteine rich domain 1

Transcriptional modification by alternative splicing is known to be involved in the regulation of programmed cell death. Recently, alternative splice variants of the TNF-related apoptosis inducing ligand (TRAIL/APO2L) and of the death receptor TRAIL-R2/DR5 have been identified. In this study, we report the identification of a novel alternative splice variant of the decoy receptor with a truncated death domain TRAIL-R4 lacking exon 3, which we designated TRAIL-R4-beta. As revealed by BLAST search we identified the genomic organisation of the TRAIL-R4 gene which consists of 9 exons. Loss of exon 3 resulted in the truncation of the first complete cysteine rich domain 1 which is known to be involved in ligand-receptor-complex. In conclusion, alternative splicing might be involved in functional fine-tuning of TRAIL-induced programmed cell death.

Apoptosis resistance in ulcerative colitis: high expression of decoy receptors by lamina propria T cells

Intestinal mucosa is constantly exposed to normal environmental antigens. A significant number of intestinal mucosal T cells are being deleted through apoptosis. In contrast, T cells from inflamed mucosa of ulcerative colitis patients did not undergo apoptosis. In this study, we determined whether the apoptosis of normal mucosal T cells was induced by antigen receptor stimulation and further determined pathways that mediated the apoptosis. Freshly isolated lamina propria T cells were stimulated with CD3 mAb and apoptosis was determined by Annexin V staining. Normal mucosal T cells underwent apoptosis upon CD3 mAb stimulation whereas the T cells from inflamed mucosa did not. The apoptosis in normal T cells was blocked by TRAIL-R1:Fc and an inhibiting CD95 antibody. Interestingly, decoy receptor (DcR)1, DcR2, and DcR3 that compete with death receptor (DR)4/5 and CD95 were highly expressed by the T cells from inflamed mucosa, but much lower by T cells from normal mucosa. Our data suggest that normal mucosal T cells are constantly deleted in response to environmental antigens mediated through DR4/5 and CD95 pathways and mucosal T cells from ulcerative colitis resist to undergoing apoptosis due to highly expression of DcR1, DcR2, and DcR3.

The systemic autoinflammatory diseases: inborn errors of the innate immune system

The autoinflammatory syndromes are a newly recognized group of immune disorders that lack the high titers of self-reactive antibodies and T cells characteristic of classic autoimmune disease. Nevertheless, patients with these illnesses experience unprovoked inflammatory disease in the absence of underlying infection. Here we discuss recent advances in eight Mendelian autoinflammatory diseases. The causative genes and the proteins they encode play a critical role in the regulation of innate immunity. Both pyrin and cryopyrin, the proteins mutated in familial Mediterranean fever and the cryopyrinopathies, respectively, are involved in regulation of the proinflammatory cytokine, IL-1beta, and may influence the activity of the transcription factor, NFkappaB. NOD2, the Blau syndrome protein, shares certain domains with cryopyrin and appears to be a sensor of intracellular bacteria. PSTPIP1, mutated in the syndrome of pyogenic arthritis with pyoderma gangrenosum and acne, interacts both with pyrin and a protein tyrosine phosphatase to regulate innate and adaptive immune responses. Somewhat unexpectedly, mutations in the p55 TNF receptor lead not to immunodeficiency but to dramatic inflammatory disease, the mechanisms of which are still under investigation. Finally, the discovery of the genetic basis of the hyperimmunoglobulinemia D with periodic fever syndrome has provided a fascinating but incompletely understood link between cholesterol biosynthesis and autoinflammation. In this manuscript, we summarize the current state of the art with regard to the diagnosis, pathogenesis, and treatment of these inborn errors of the innate immune system.

Rheumatoid arthritis is associated with increased aortic pulse-wave velocity, which is reduced by anti-tumor necrosis factor-alpha therapy

BACKGROUND

Rheumatoid arthritis (RA) is associated with increased cardiovascular risk, which is not explained by traditional cardiovascular risk factors but may be due in part to increased aortic stiffness, an independent predictor of cardiovascular mortality. In the present study, our aim was to establish whether aortic stiffness is increased in RA and to investigate the relationship between inflammation and aortic stiffness. In addition, we tested the hypothesis that aortic stiffness could be reduced with anti-tumor necrosis factor-alpha (TNF-alpha) therapy.

METHODS AND RESULTS

Aortic pulse-wave velocity (PWV), augmentation index, and blood pressure were measured in 77 patients with RA and in 142 healthy individuals. Both acute and chronic inflammatory measures and disease activity were determined. The effect of anti-TNF-alpha therapy on PWV and endothelial function was measured in 9 RA patients at 0, 4, and 12 weeks. Median (interquartile range) aortic PWV was significantly higher in subjects with RA than in control subjects (8.35 [7.14 to 10.24] versus 7.52 [6.56 to 9.18] m/s, respectively; P = 0.005). In multiple regression analyses, aortic PWV correlated independently with age, mean arterial pressure, and log-transformed C-reactive protein (R2 = 0.701; P < 0.0001). Aortic PWV was reduced significantly by anti-TNF-alpha therapy (8.82+/-2.04 versus 7.94+/-1.86 versus 7.68+/-1.56 m/s at weeks 0, 4, and 12, respectively; P < 0.001); concomitantly, endothelial function improved.

CONCLUSIONS

RA is associated with increased aortic stiffness, which correlates with current but not historical measures of inflammation, suggesting that increased aortic stiffness may be reversible. Indeed, anti-TNF-alpha therapy reduced aortic stiffness to a level comparable to that of healthy individuals. Therefore, effective control of inflammation may be of benefit in reducing cardiovascular risk in patients with RA.

Tumor necrosis factor receptor regulation of bone marrow cell apoptosis during endotoxin-induced systemic inflammation

Although inflammation-induced release of cells from the bone marrow (BM) is well established, less is known regarding inflammation-induced modulation of bone marrow cell numbers by apoptosis. The purpose of this study is to assess apoptosis of BM immature and mature myeloid cells and peripheral granulocytes, and to elucidate the role(s) of TNFR-p55 and TNFR-p75 as modulators of apoptosis in these cellular compartments in a mouse model of endotoxin-induced systemic inflammation. Gene knockout (p55(-/-), p75(-/-), and p55(-/-)/p75(-/-)), or wild-type (WT) mice were injected i.p. with saline (Sal) or LPS (4 microg/g) followed by collection of BM cells and peripheral blood after 24 h. Apoptosis was assessed by propidium iodide staining using two-color flow cytometry with differentiated granulocyte-specific Gr1-fluorescein isothiocyanate. Repeated-measures analysis of variance and Neuman-Keuls post hoc test were used for statistical analyses. After i.p. LPS, apoptosis was induced to the higher level in BM Gr1(-) cells than in BM Gr1(+) cells and was not induced in peripheral Gr1(+) cells. Depletion of cell numbers in both BM Gr1(-) and Gr1(+) subpopulations after LPS treatment was consistent with increase of the apoptotic cell percentages in the groups. LPS-induced apoptosis was significantly lower in Gr1(-) cells from the -p55(-/-)/LPS and p55(-/-)/p75(-/-)/LPS mice but not from p75(-/-)/LPS mice as compared with WT/LPS mice, whereas there was no difference in apoptosis of BM Gr1(+) and peripheral Gr1(+) cells among WT groups and knockout groups. Thus, apoptosis of myeloid cells during endotoxemia is minimized because these cells undergo differentiation, which in turn may be because of the attenuation of the proapoptotic effect of TNFR-p55 shown herein to occur with myeloid differentiation. In contrast, TNFR-p75 seems to play a minimal role in apoptosis induction in Gr1(-) myeloid cells during endotoxemia. One explanation for a decrease in BM cell numbers during endotoxemia may be via induction of apoptosis in immature myeloid cells.

Tumor necrosis factor receptor 1 signaling resistance in the female myocardium during ischemia

BACKGROUND

Tumor necrosis factor-alpha (TNF) is increased in myocardial tissue after ischemia and reperfusion (I/R). TNF contributes to postischemic myocardial dysfunction and induces proinflammatory signaling, which may be mediated by the 55-kDa TNF receptor (TNFR1). In humans, there is a direct correlation between functional capacity, survival, and circulating TNF levels. Although decreasing the TNF level in animals was beneficial after myocardial ischemia, simply decreasing the bioavailability of TNF in humans with heart failure was not beneficial. This led to the important appreciation that TNF may have beneficial or deleterious effects in the heart, depending on which of its receptors is activated. Females have a lower incidence of heart failure and a higher heart failure survival than males. We hypothesized that TNFR1 signaling resistance occurs in the female myocardium during ischemia.

METHODS AND RESULTS

Hearts from male and female TNFR1-knockout and wild-type (WT) mice were subjected to I/R. Female WT mice had better postischemic recovery than did male WT mice, an effect that appeared to be due to TNFR1 signaling resistance in females. Female WT mice had less myocardial depression after TNF infusion despite equivalent TNFR1 expression. Interestingly, TNFR1 ablation improved postischemic myocardial function, decreased activation of p38 mitogen-activated protein kinase, and reduced expression of interleukins-1beta and -6 in males but not in females. Furthermore, WT females expressed more of the suppressor of cytokine signaling protein 3 after I/R, which may in part explain TNFR1 signaling resistance in the female myocardium.

CONCLUSIONS

This study demonstrates that sex differences exist in myocardial TNF signaling by TNFR1 after I/R.

Survivin inhibits apoptosis induced by TRAIL, and the ratio between survivin and TRAIL receptors is predictive of recurrent disease in neuroblastoma

PURPOSE

Novel treatment strategies for high-risk and disseminated neuroblastoma (NB) are actively sought because of the dismal prognosis of advanced stage disease. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a recently identified member of the tumor necrosis factor family. TRAIL is capable of inducing apoptosis in multiple tumor cell types, with little or no cytotoxicity against normal cells.

EXPERIMENTAL DESIGN

We examined the activation and regulation of TRAIL-induced apoptosis in several human NB cell lines. The effect of TRAIL was examined in the context of TRAIL receptor (TRAIL-R) and survivin (an antiapoptotic protein) expression in the cell lines. The ratio of survivin/TRAIL-R messenger RNA was determined and evaluated as a marker of recurrent disease in patients with NB.

RESULTS

TRAIL induced apoptotic cell death of NB with variable sensitivities among the cell lines tested. Compared with a sensitive cell line (early passage NB16), the resistant cell lines (NB7 and late passage NB16) expressed lesser amounts of the death-inducing TRAIL-R1 and R2, and greater levels of survivin, an inhibitor of apoptosis. TRAIL sensitivity was enhanced in resistant cell lines by treating with etoposide that concomitantly increased TRAIL-R expression and diminished survivin expression. Survivin overexpression in a TRAIL-sensitive NB line (early passage NB16) rendered it less sensitive to treatment with TRAIL. Conversely, inhibiting survivin expression in NB3 by antisense oligonucleotides enhanced TRAIL sensitivity. A high survivin/TRAIL-R ratio accurately predicted risk for recurrent disease in primary tumor specimens tested.

CONCLUSIONS

These findings suggest that TRAIL therapy in combination with specific chemotherapeutic agents may represent an effective therapeutic strategy for NB. The cell's sensitivity to TRAIL is at least partially governed by both TRAIL-R and survivin expression, whereas the ratio between these 2 factors appears to have prognostic value in patients with this disease.

Variation in Ligand Binding Specificities of a Novel Class of Poxvirus-encoded Tumor Necrosis Factor-binding Protein

The Yatapoxviruses encode a distinct class of secreted TNF-binding protein (TNF-BP) that resembles an MHC class I heavy chain but distinct from any other known TNF inhibitor. Characterization of these viral TNF inhibitors from Tanapox virus, Yaba monkey tumor virus (YMTV) and a closely related version from Swinepox virus revealed dramatically differential TNF binding specificities for different mammalian species. The Tanapox virus 2L protein (TPV-2L) formed inhibitory complexes with human TNF, and interacted with monkey and canine TNF with high affinity but rabbit TNF with low affinity. On the other hand, YMTV-2L bound human and monkey TNF with high affinity but rabbit TNF with only low affinity. The TNF-BP from swinepox virus (SPV003/148) only interacted with porcine TNF with high affinity. The observed TNF binding analysis mirrored the biological activity of these TNF-binding protein to block TNF-induced cellular cytolysis. TPV-2L and YMTV-2L also inhibited the human TNF-mediated signaling in cells but TPV-2L exhibited higher affinity for human TNF (KD, 43 pm) compared with monkey (KD, 120 pm) whereas for YMTV-2L, the affinities were reversed (human TNF KD, 440 pm; monkey TNF KD, 230 pm). The interaction domain of human TNF with TNF-binding proteins is significantly different from that of TNFRs, as determined using human TNF mutants. We conclude that these poxvirus TNF-binding proteins represent a new class of TNF inhibitors and are distinct from the viral TNF receptor homologues characterized to date.

The role of tumor necrosis factor-alpha in the neuropathic pain induced by Lumbar 5 ventral root transection in rat

Accumulating evidence has demonstrated that tumor necrosis factor-alpha (TNF-alpha) plays an important role in neuropathic pain. Recently, it has been shown that Lumbar 5 ventral root transection (L5 VRT) induces persistent mechanical allodynia and thermal hyperalgesia in bilateral hind paws. In the present study, the role of TNF-alpha in the L5 VRT model was investigated. We found that immunoreactivity (IR) of TNF-alpha and TNF receptor 1 (TNFR1) in ipsilateral (but not in contralateral) L4 and L5 dorsal root ganglion (DRG) was increased following L5 VRT, started 1 day after the lesion and persisted for 2 weeks. Double immunofluorescence staining revealed that the increased TNF-alpha-IR in DRG was in satellite glial cells, immune cells and neuronal cells, while TNFR1-IR was almost restricted at DRG neuronal cells. L5 VRT increased TNF-alpha-IR and TNFR1-IR in bilateral L5 spinal dorsal horn, started 1 day after lesion and persisted for 2 weeks. The increased TNF-alpha-IR in spinal dorsal horn was observed in astrocytes, microglias and neurons, but the upregulation of TNFR1 was mainly in neurons. Intraperitoneal injection of thalidomide, an inhibitor of TNF-alpha synthesis, started at 2h before surgery, blocked mechanical allodynia and thermal hyperalgesia. However, the drug failed to reverse the abnormal pain behaviors, when it was applied at day 7 after surgery. These data suggest that the upregulation of TNF-alpha and TNFR1 in DRG and spinal dorsal horn is essential for the initiation but not for maintenance of the neuropathic pain induced by L5 VRT.

New therapeutic strategies and drug candidates for neurodegenerative diseases: p53 and TNF-alpha inhibitors, and GLP-1 receptor agonists

Owing to improving preventative, diagnostic, and therapeutic measures for cardiovascular disease and a variety of cancers, the average ages of North Americans and Europeans continue to rise. Regrettably, accompanying this increase in life span, there has been an increase in the number of individuals afflicted with age-related neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, and stroke. Although different cell types and brain areas are vulnerable among these, each disorder likely develops from activation of a common final cascade of biochemical and cellular events that eventually lead to neuronal dysfunction and death. In this regard, different triggers, including oxidative damage to DNA, the overactivation of glutamate receptors, and disruption of cellular calcium homeostasis, albeit initiated by different genetic and/or environmental factors, can instigate a cascade of intracellular events that induce apoptosis. To forestall the neurodegenerative process, we have chosen specific targets to inhibit that are at pivotal rate-limiting steps within the pathological cascade. Such targets include TNF-alpha, p53, and GLP-1 receptor. The cytokine TNF-alpha is elevated in Alzheimer's disease, Parkinson's disease, stroke, and amyotrophic lateral sclerosis. Its synthesis can be reduced via posttranscriptional mechanisms with novel analogues of the classic drug, thalidomide. The intracellular protein and transcription factor, p53, is activated by the Alzheimer's disease toxic peptide, Abeta, as well as by excess glutamate and hypoxia to trigger neural cell death. It is inactivated by novel tetrahydrobenzothiazole and -oxazole analogues to rescue cells from lethal insults. Stimulation of the glucagon-like peptide-1 receptor (GLP-1R) in brain is associated with neurotrophic functions that, additionally, can protect cells against excess glutamate and other toxic insults.

Onercept for moderate-to-severe Crohn's disease: a randomized, double-blind, placebo-controlled trial

BACKGROUND AND AIMS

Onercept is a recombinant, soluble human p55 receptor to tumor necrosis factor-alpha.

METHODS

A randomized, double-blind, placebo-controlled, dose-ranging trial was performed to evaluate the efficacy of onercept induction therapy in patients with Crohn's disease (CD). Patients (n = 207) with moderate-to-severe acute or chronic active CD were randomized to receive subcutaneous onercept (10, 25, 35, or 50 mg) or placebo 3 times weekly for 8 weeks. Primary analysis was induction of remission (defined as a CD activity index score < or = 150) at week 8.

RESULTS

A total of 104 patients had acute active CD. Remission rates at week 8 were 23.5% for placebo (n = 17), and 34.8%, 20.0%, 26.1%, and 28.6% for onercept 10 mg (n = 23), 25 mg (n = 20), 35 mg (n = 23), and 50 mg (n = 21), respectively (P = .98). A total of 103 patients had chronic active CD. Remission rates at week 8 were 23.8% for placebo (n = 21), and 23.8%, 9.1%, 35.3%, and 13.6% for onercept 10 mg (n = 21), 25 mg (n = 22), 35 mg (n = 17), and 50 mg (n = 22), respectively (P = .66). There were no differences between treatment groups in the incidence of adverse events. However, mild-to-moderate injection-site reactions occurred in up to 12% of onercept-treated patients.

CONCLUSIONS

Onercept was well tolerated but was not effective at the doses studied in patients with active CD.

TNF-alpha is necessary for induction of coronary artery inflammation and aneurysm formation in an animal model of Kawasaki disease

Kawasaki disease is the most common cause of multisystem vasculitis in childhood. The resultant coronary artery lesions make Kawasaki disease the leading cause of acquired heart disease in children in the developed world. TNF-alpha is a pleiotropic inflammatory cytokine elevated during the acute phase of Kawasaki disease. In this study, we report rapid production of TNF-alpha in the peripheral immune system after disease induction in a murine model of Kawasaki disease. This immune response becomes site directed, with migration to the coronary arteries dependent on TNF-alpha-mediated events. Production of TNF-alpha in the heart is coincident with the presence of inflammatory infiltrate at the coronary arteries, which persists during development of aneurysms. More importantly, inflammation and elastin breakdown in the coronary vessels are completely eliminated in the absence of TNF-alpha effector functions. Mice treated with the TNF-alpha-blocking agent etanercept, as well as TNFRI knockout mice, are resistant to development of both coronary arteritis and coronary aneurysm formation. Taken together, TNF-alpha is necessary for the development of coronary artery lesions in an animal model of Kawasaki disease. These findings have important implications for potential new therapeutic interventions in children with Kawasaki disease.

Sensitivity of prostate cells to TRAIL-induced apoptosis increases with tumor progression: DR5 and caspase 8 are key players

BACKGROUND

As advanced prostate cancers are resistant to currently available chemotherapies, we evaluated the cytotoxic effect of TNF-related apoptosis-inducing ligand (TRAIL) and characterized the involvement of its five receptors DR4, DR5, DcR1, DcR2, and osteoprotegerin (OPG) and of the death-inducing signaling complex (DISC)-forming proteins caspase 8 and c-FLIP in prostate cell lines.

METHODS

We used six prostate cell lines, each corresponding to a particular stage in prostate tumorigenesis, and analyzed TRAIL sensitivity in relation to TRAIL receptors' expression.

RESULTS

TRAIL sensitivity was correlated with tumor progression and DR5 expression levels and apoptosis was exclusively mediated by DR5. DcR2 was significantly more abundant in tumor cells than in non-neoplastic ones and may contribute to partial resistance to TRAIL in some prostate tumor cells. Conversely, non-tumoral cells secreted high levels of OPG, which can protect them from apoptosis. Finally, caspase 8 expression levels were as DR5 directly correlated to TRAIL sensitivity in prostate tumor cells.

CONCLUSION

TRAIL-induced apoptosis is closely related to the balanced expression of its different receptors in prostate cancer cells and their modulation could be of potential clinical value for advanced tumor treatment.

PanR1, a Dominant Negative Missense Allele of the Gene Encoding TNF-α (Tnf), Does Not Impair Lymphoid Development

A dominant hypomorphic allele of Tnf, PanR1, was identified in a population of G(1) mice born to N-ethyl-N-nitrosourea-mutagenized sires. Macrophages from homozygotes produced no detectable TNF bioactivity, although normal quantities of immunoreactive TNF were secreted. The phenotype was confined to a critical region on mouse chromosome 17, and then ascribed to a C-->A transversion at position 3480 of the Tnf gene, corresponding to the amino acid substitution P138T. As a result of subunit exchange, the protein exerts a dominant-negative effect on normal TNF trimers, interfering with the trimer/receptor interaction. Homozygotes are highly susceptible to infection by Listeria monocytogenes, confirming the essential role of TNF in innate immune defense. However, PanR1 mutant mice show normal architecture of the spleen and Peyer's patches, suggesting that TNF is not essential for the formation of these lymphoid structures.

Mice lacking both TNFα receptors show increased constitutive expression of IFNγ: A possible reason for lack of protection from fumonisin B1 hepatotoxicity☆

Fumonisin B1 is a mycotoxin prevalent in corn that produces species-, gender-, and organ-specific diseases. Mice lacking TNFalpha receptor (TNFR) 1 or 2 exhibited a diminished hepatotoxic response to fumonisin B1; however, the protection was lost when both TNFRs were deleted. We therefore investigated the constitutive expression of selected apoptotic factors and their response to fumonisin B1 in the liver from mice lacking both TNFRs (DRKO). Compared to their wild-type (WT) counterparts the DRKO strain had a higher constitutive mRNA expression of interferon (IFN)gamma, Fas, and interleukin (IL)-18. The mRNA expression of Bcl-2 was also higher in DRKO than in WT mice. The mRNA expression of IL-1 receptor antagonist (IL-1Ra) was decreased; that of TNF-related apoptosis-inducing ligand (TRAIL) was dramatically reduced. Induction of most apoptotic genes in response to fumonisin B1 was similar in both WT and DRKO strains; except in DRKO mice it was greater for Max and lesser for IL-1Ra than that in WT strain. Fumonisin B1 hepatotoxicity in DRKO mice was reduced by pretreatment with anti-IFNgamma antibody. It appears that in the absence of TNFalpha signaling other apoptotic pathways become operative; particularly the increase of IFNgamma, Fas and IL-18 may compensate for the loss of TNFalpha effects. Fumonisin B1 toxicity therefore appears to be a complex phenomenon that may utilize more than one cytotoxic pathway consequent to sphingoid deregulation; a higher expression of IFNgamma and other apoptotic factors in DRKO may be responsible for the observed fumonisin hepatotoxicity.

A tumor necrosis factor receptor 1-dependent conversation between central nervous system-specific T cells and the central nervous system is required for inflammatory infiltration of the spinal cord

We examined the role of tumor necrosis factor receptor 1 (TNFR1) in inflammation initiated by the adoptive transfer of central nervous system (CNS)-specific Th1 cells in experimental autoimmune encephalomyelitis, a murine model of multiple sclerosis. This adoptive transfer paradigm eliminates the confounding effects of bacterial adjuvants in the analysis of inflammation. We found that although T cells could reach the meninges and perivascular space in the absence of TNFR1, recruitment of other inflammatory cells from the blood was dramatically reduced. The reduction in the recruitment of CD11b(hi) cells correlated with a dramatic reduction in the production of the chemokines CCL2 (MCP-1) and CXLC2 (MIP-2) in TNFR1-deficient hosts. Bone marrow chimera experiments demonstrated that TNF can be effectively supplied by either the hematopoietic system or the CNS, but the essential TNFR1-responsive cells reside in the CNS. Previous work has demonstrated that microglia produce CCL2, and here we demonstrate that astrocytes and endothelial cells produced CXCL2 in the early stages of inflammation. Therefore, productive inflammation results from a conversation, or mutually responding signals, between the initiating T cells and cells in the parenchyma of the spinal cord.

TNFalpha signaling in depression and anxiety: behavioral consequences of individual receptor targeting

BACKGROUND

Increased serum levels of TNFalpha and other pro-inflammatory cytokines have been found in patients with major depression and several other psychiatric conditions. In rodents, these cytokines produce symptoms commonly referred to as "sickness behavior." Some of these, including reduced feeding and decreased social and exploratory behavior, are reminiscent of those seen in depressed patients. Interpretation of these effects is complicated by the malaise caused by acute injections of pro-inflammatory cytokines, however. Thus, it is unclear whether cytokines are involved in the etiology of depressive symptoms.

METHODS

We used a panel of behavioral assays to assess TNFR1(-/-) and TNFR2(-/-) mice for anxiety and depression-like behaviors.

RESULTS

We show that deletion of either TNFR1 or TNFR2 leads to an antidepressant-like response in the forced swim test and that mice lacking TNFR2 demonstrate a hedonic response in a sucrose drinking test compared with wildtype littermates. In addition, deletion of TNFR1 leads to decreased fear conditioning. There were no differences in behavior in anxiety tests for either null mutant.

CONCLUSIONS

These results are consistent with the hypothesis that TNFalpha can induce depression-like symptoms even in the absence of malaise and demonstrate that both receptor subtypes can be involved in this response.

Differential role of tumor necrosis factor receptors in mouse brain inflammatory responses in cryolesion brain injury

Tumor necrosis factor-alpha (TNF-alpha) is one of the mediators dramatically increased after traumatic brain injury that leads to the activation, proliferation, and hypertrophy of mononuclear, phagocytic cells and gliosis. Eventually, TNF-alpha can induce both apoptosis and necrosis via intracellular signaling. This cytokine exerts its functions via interaction with two receptors: type-1 receptor (TNFR1) and type-2 receptor (TNFR2). In this work, the inflammatory response after a freeze injury (cryolesion) in the cortex was studied in wild-type (WT) animals and in mice lacking TNFR1 (TNFR1 KO) or TNFR2 (TNFR2 KO). Lack of TNFR1, but not of TNFR2, significantly decreased the inflammatory response and tissue damage elicited by the cryolesion at both 3 and 7 days postlesion, with decreased gliosis, lower IL-1beta immunostaining, and a reduction of apoptosis markers. Cryolesion produced a clear induction of the proinflammatory cytokines interleukin (IL)-1alpha, IL-1beta, IL-6, and TNF-alpha; this induction was significantly lower in the TNFR1 KO mice. Host response genes (ICAM-1, A20, EB22/5, and GFAP) were also induced by the cryolesion, but to a lesser extent in TNFR1 KO mice. Lack of TNFR1 signaling also affected the expression of apoptosis/cell death-related genes (Fas, Rip, p53), matrix metalloproteinases (MMP3, MMP9, MMP12), and their inhibitors (TIMP1), suggesting a role of TNFR1 in extracellular matrix remodeling after injury. However, GDNF, NGF, and BDNF expression were not affected by TNFR1 deficiency. Overall, these results suggest that TNFR1 is involved in the early establishment of the inflammatory response and that its deficiency causes a decreased inflammatory response and tissue damage following brain injury.

Preclinical differentiation between apparently safe and potentially hepatotoxic applications of TRAIL either alone or in combination with chemotherapeutic drugs

PURPOSE

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) exhibits potent antitumor activity on systemic administration in nonhuman primates without deleterious side effects for normal tissue. However, there is a controversy about the potential toxicity of TRAIL on human hepatocytes. The use of different recombinant TRAIL forms only partially explains the contradicting reports on TRAIL sensitivity in primary human hepatocytes (PHH).

EXPERIMENTAL DESIGN

To clarify this issue, we comprehensively tested four different recombinant forms of TRAIL for their apoptosis-inducing capacity on PHH obtained from a total of 55 human livers between day 1 and day 8 of in vitro culture.

RESULTS

One day after single-cell isolation, all but one recombinant form of TRAIL [i.e., an untagged form of TRAIL (TRAIL.0)] induced apoptosis in PHH. Apoptosis induction by TRAIL in these cells could only be fully inhibited by concomitant blockade of TRAIL receptor 1 and TRAIL receptor 2. At day 4 of in vitro culture, when surrogate markers indicated optimal hepatocyte in vitro function, only high doses of cross-linked FLAG-TRAIL killed PHH whereas the other three recombinant TRAIL forms did not. Strikingly, cotreatment of day 4 PHH with cisplatin sensitized for TRAIL-induced apoptosis whereas 5-fluorouracil, etoposide, gemcitabine, irinotecan, or oxaliplatin, which are commonly used in the treatment of gastrointestinal cancers, did not.

CONCLUSION

Our data show that whereas TRAIL alone or together with selected chemotherapeutic drugs seems to be safe, the combination of TRAIL with cisplatin is toxic to PHH.

Drug Insight: antagonists of tumor-necrosis factor-α in the treatment of inflammatory bowel disease

In the past decade, advances in the understanding of the pathogenesis of inflammatory bowel disease have permitted the development of agents directed against rational therapeutic targets. In particular, various antagonists of tumor-necrosis factor-alpha have been developed. These include infliximab, adalimumab, certolizumab (CDP870), CDP571, etanercept, and onercept. Clinical trials of these agents have demonstrated varying degrees of clinical efficacy. The use of these agents can be limited by infection, immunogenicity, acute infusion reactions, delayed hypersensitivity reactions, and autoimmune phenomena. This review provides insights into the use of antagonists of tumor-necrosis factor-alpha for the treatment of inflammatory bowel disease.

Tamoxifen protects against acute tumor necrosis factor alpha-induced cardiac injury via improving mitochondrial functions

Tamoxifen is the most commonly used antiestrogen for the treatment of breast cancer. Several clinical trials demonstrate that tamoxifen reduces the risk of heart disease and osteoporosis. However, the mechanism by which tamoxifen causes cardioprotection is unclear. Because increased levels of tumor necrosis factor alpha (TNFalpha) in tissue and/or plasma have been observed in virtually all forms of cardiac injury, we investigated whether tamoxifen prevents cardiac injury in a murine model of acute TNFalpha challenge. Five- to six-week-old female mice were injected (ip) with tamoxifen at 0.25 mg/kg daily for 3 or 7 days before receiving an injection of TNFalpha. Ultrastructural examination of cardiac tissues revealed remarkable protection against TNFalpha-induced mitochondrial damage in tamoxifen pretreated mice. Tamoxifen treatment significantly improved the mitochondrial respiratory function and enhanced superoxide-scavenging activity of mitochondria. These findings reveal a novel mitochondria-mediated mechanism by which tamoxifen exerts its cardiac protection effect against acute TNFalpha-induced heart injury.

Efficiency of recombinant human TNF in human cancer therapy

Recombinant human tumour necrosis factor (TNF) has a selective effect on angiogenic vessels in tumours. Given that it induces vasoplegia, its clinical use has been limited to administration through isolated limb perfusion (ILP) for regionally advanced melanomas and soft tissue sarcomas of the limbs. When combined with the alkylating agent melphalan, a single ILP produces a very high objective response rate. In melanoma, the complete response (CR) rate is around 80% and the overall objective response rate greater than 90%. In soft tissue sarcomas that are inextirpable, ILP is a neoadjuvant treatment resulting in limb salvage in 80% of the cases. The CR rate averages 20% and the objective response rate is around 80%. The mode of action of TNF-based ILP involves two distinct and successive effects on the tumour-associated vasculature: first, an increase in endothelium permeability leading to improved chemotherapy penetration within the tumour tissue, and second, a selective killing of angiogenic endothelial cells resulting in tumour vessel destruction. The mechanism whereby these events occur involves rapid (of the order of minutes) perturbation of cell-cell adhesive junctions and inhibition of alphavbeta3 integrin signalling in tumour-associated vessels, followed by massive death of endothelial cells and tumour vascular collapse 24 hours later. New, promising approaches for the systemic use of TNF in cancer therapy include TNF targeting by means of single chain antibodies or endothelial cell ligands, or combined administration with drugs perturbing integrin-dependent signalling and sensitizing angiogenic endothelial cells to TNF-induced death.

The E3 ubiquitin ligase itch couples JNK activation to TNFalpha-induced cell death by inducing c-FLIP(L) turnover

The proinflammatory cytokine tumor necrosis factor (TNF) alpha signals both cell survival and death. The biological outcome of TNFalpha treatment is determined by the balance between NF-kappaB and Jun kinase (JNK) signaling; NF-kappaB promotes survival, whereas JNK enhances cell death. Critically, identity of a JNK substrate that promotes TNFalpha-induced apoptosis has been outstanding. Here we show that TNFalpha-mediated JNK activation accelerates turnover of the NF-kappaB-induced antiapoptotic protein c-FLIP, an inhibitor of caspase-8. This is not due to direct c-FLIP phosphorylation but depends on JNK-mediated phosphorylation and activation of the E3 ubiquitin ligase Itch, which specifically ubiquitinates c-FLIP and induces its proteasomal degradation. JNK1 or Itch deficiency or treatment with a JNK inhibitor renders mice resistant in three distinct models of TNFalpha-induced acute liver failure, and cells from these mice do not display inducible c-FLIP(L) ubiquitination and degradation. Thus, JNK antagonizes NF-kappaB during TNFalpha signaling by promoting the proteasomal elimination of c-FLIP(L).

Dissociation between increased apoptosis and expression of the tumor necrosis factor-alpha system in term placental villi with preeclampsia

OBJECTIVE

To analyse in situ the placental expression of tumor necrosis factor-alpha (TNF-alpha), its receptors TNFRp55 and TNFRp75, and apoptosis in normotensive and preeclamptic pregnancies.

DESIGN AND METHODS

We simultaneously analyzed the immunostaining of TNF-alpha, its receptors and apoptosis in term placentas of 15 patients with preeclampsia and 15 normotensive pregnant women as controls.

RESULTS

In normotensive villi TNF-alpha and TNFRp75 were expressed more in syncytiotrophoblasts than cytotrophoblasts or stromal cells, and were almost absent in endothelial cells. TNFRp55 was expressed uniformly in all types of placental cells. Apoptosis was more marked in syncytiotrophoblasts than cytotrophoblasts. In preeclamptic trophoblasts apoptosis was exaggerated whereas expression of TNF-alpha and its receptors remained unchanged.

CONCLUSIONS

Placental expression of TNF-alpha and TNFRp75 appear inter-adaptative and follow the same pattern, whereas TNFRp55 and TNF-alpha appear independent. In addition, the exaggerated apoptosis of preeclamptic trophoblasts may be dependent on factors other than the TNF-alpha system alone.

Inflammatory signalling pathways involved in astroglial activation by unconjugated bilirubin

During neonatal hyperbilirubinaemia, astrocytes activated by unconjugated bilirubin (UCB) may contribute to brain toxicity through the production of cytokines. As a first step in addressing the signal transduction cascades involved in the UCB-induced astroglial immunological response, we tested whether tumour necrosis factor (TNF)-alpha receptor 1 (TNFR1), mitogen-activated protein kinase (MAPK) and nuclear factor kappaB (NF-kappaB) would be activated in astrocytes exposed to UCB, and examined the profile of cytokine production. Astrocyte cultures stimulated with UCB showed a rapid rise in TNFR1 protein levels, followed by activation of the MAPKs p38, Jun N-terminal kinase1/2 and extracellular signal-regulated kinase1/2, and NF-kappaB. Interestingly, the induction of these signal effectors preceded the early up-regulation of TNF-alpha and interleukin (IL)-1beta mRNAs, and later secretion of TNF-alpha, IL-1beta and IL-6. Treatment of astrocytes with UCB also induced cell death, with levels comparable to those obtained after exposure of astrocytes to recombinant TNF-alpha and IL-1beta. Moreover, loss of cell viability and cytokine secretion were reduced when the NF-kappaB signal transduction pathway was inhibited, suggesting a key role for NF-kappaB in the astroglial response to UCB. These results demonstrate the complexity of the molecular mechanisms involved in cell injury by UCB during hyperbilirubinaemia and provide a basis for the development of novel therapeutic strategies.

Rapid TNFR1-dependent lymphocyte depletion in vivo with a selective chemical inhibitor of IKKbeta

The transcription factor NF-kappaB plays a central role in regulating inflammation and apoptosis, making it a compelling target for drug development. We identified a small molecule inhibitor (ML120B) that specifically inhibits IKKbeta, an Ikappa-B kinase that regulates NF-kappaB. IKKbeta and NF-kappaB are required in vivo for prevention of TNFalpha-mediated apoptosis. ML120B sensitized mouse bone marrow progenitors and granulocytes, but not mature B cells to TNFalpha killing in vitro, and induced apoptosis in vivo in the bone marrow and spleen within 6 hours of a single oral dose. In vivo inhibition of IKKbeta with ML120B resulted in depletion of thymocytes and B cells in all stages of development in the bone marrow but did not deplete granulocytes. TNF receptor-deficient mouse thymocytes and B cells were resistant to ML120B-induced depletion in vivo. Surprisingly, surviving bone marrow granulocytes expressed TNFR1 and TNFR2 after dosing in vivo with ML120B. Our results show that inhibition of IKKbeta with a small molecule in vivo leads to rapid TNF-dependent depletion of T and B cells. This observation has several implications for potential use of IKKbeta inhibitors for the treatment of inflammatory disease and cancer.

TNFR1 mediates increased neuronal membrane EAAT3 expression after in vivo cerebral ischemic preconditioning

A short ischemic event (ischemic preconditioning) can result in subsequent resistance to severe ischemic injury (ischemic tolerance). Glutamate is released after ischemia and produces cell death. It has been described that after ischemic preconditioning, the release of glutamate is reduced. We have shown that an in vitro model of ischemic preconditioning produces upregulation of glutamate transporters which mediates brain tolerance. We have now decided to investigate whether ischemic preconditioning-induced glutamate transporter upregulation takes also place in vivo, its cellular localization and the mechanisms by which this upregulation is controlled. A period of 10 min of temporary middle cerebral artery occlusion was used as a model of ischemic preconditioning in rat. EAAT1, EAAT2 and EAAT3 glutamate transporters were found in brain from control animals. Ischemic preconditioning produced an up-regulation of EAAT2 and EAAT3 but not of EAAT1 expression. Ischemic preconditioning-induced increase in EAAT3 expression was reduced by the TNF-alpha converting enzyme inhibitor BB1101. Intracerebral administration of either anti-TNF-alpha antibody or of a TNFR1 antisense oligodeoxynucleotide also inhibited ischemic preconditioning-induced EAAT3 up-regulation. Immunohistochemical studies suggest that, whereas the expression of EAAT3 is located in both neuronal cytoplasm and plasma membrane, ischemic preconditioning-induced up-regulation of EAAT3 is mainly localized at the plasma membrane level. In summary, these results demonstrate that in vivo ischemic preconditioning increases the expression of EAAT2 and EAAT3 glutamate transporters the upregulation of the latter being at least partly mediated by TNF-alpha converting enzyme/TNF-alpha/TNFR1 pathway.

Peptide vaccination of mice immune to LCMV or vaccinia virus causes serious CD8 T cell-mediated, TNF-dependent immunopathology

CD8 T cells play a key role in clearing primary virus infections and in protecting against subsequent challenge. The potent antiviral effects of these cells make them important components of vaccine-induced immunity and, because of this, peptide vaccines often contain epitopes designed to induce strong CD8 T cell responses. However, the same effector functions that protect the host also can be harmful if they are not tightly regulated, and virus-specific CD8 T cells are a frequent cause of immunopathology. Here, we report that the administration of peptide to virus-immune recipient mice can lead to the synchronous activation of preexisting virus-specific CD8 T cells with serious, and even lethal, consequences. Mice infected with LCMV or vaccinia virus developed rapid and profound hypothermia following injection of cognate synthetic peptides, and LCMV-infected mice frequently died within hours. Detailed analyses of the LCMV infected mice revealed enterocyte apoptosis and implicated TNF produced by peptide-specific CD8 T cells as the major mediator of disease. The caspase inhibitor zVADfmk had no demonstrable effect on the development of hypothermia, but diminished enterocyte apoptosis and greatly reduced the number of deaths. These findings, if similarly observed in patients, counsel caution when administering powerful immunogens such as peptide vaccines to individuals who may have a large preexisting pool of epitope-specific CD8 T cells.

Nanofunctionalisation for the treatment of peripheral nervous system injuries

A construct based on the electrostatic layer-by-layer self assembly technique has been fabricated, to be used as a tailored device to encourage nerve regeneration. A multilayered nanocoating composed of three precursor bilayers of cationic poly(dimethyldiallylammonium) chloride (PDDA) and anionic poly(styrenesulfonate) (PSS), followed by bilayers of poly-D-lysine (PDL) and antibody specific to transforming growth factor 1 (anti-TGF-1), has been deposited on HYAFF 11. The assembly process has been monitored by quartz crystal microbalance (QCM) for its characterisation and then it has been used on HYAFF 11. Structural studies of the resulting multilayers confirmed stepwise deposition of anti-TGF-1, with an average layer thickness of 2.2+/-0.2 nm and an average surface density of 0.36+/-0.03 mug cm(-2). Scanning electron microscopy has been used to characterise multilayer uniformity. Finally, the immunological activity of the multilayered structure has been assessed. The results show that anti-TGF-1 can be included in its active form in a predetermined multilayered structure onto HYAFF 11 with quantitative control of layer thickness and weight, providing a high tool with great potential in tissue engineering.

Aberrant expression of TRAIL in B chronic lymphocytic leukemia (B-CLL) cells

Analysis of peripheral blood (>85% CD19+/CD5+ B) lymphocytes, obtained from 44 patients affected by B chronic lymphoid leukemia (B-CLL), showed that surface TNF-related apoptosis inducing ligand (TRAIL) was expressed in all samples and at higher levels with respect to unfractionated lymphocytes and purified CD19+ B cells, obtained from 15 normal blood donors. Of note, in a subset of B-CLL samples, the addition to B-CLL cultures of a TRAIL-R1-Fc chimera, which binds at high affinity to surface TRAIL, significantly decreased the percentage of viable cells with respect to untreated control B-CLL cells, suggesting that surface TRAIL may play an unexpected role in promoting B-CLL cell survival. In spite of the majority of B-CLL lymphocytes expressed variable surface levels of "death receptors" TRAIL-R1 and TRAIL-R2, the addition in culture of recombinant TRAIL increased (>20% vs. controls) the degree of spontaneous apoptosis in only 11/44 of the B-CLL samples, had no effect in 19/44, while it significantly increased leukemic cell survival in 14/44. Taken together, these findings suggest that an aberrant expression of TRAIL might contribute to the pathogenesis of B-CLL by promoting the survival in a subset of B-CLL cells.

Decoy receptor 2 (DcR2) is a p53 target gene and regulates chemosensitivity

Decoy receptor 2 (DcR2) is one of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors and suppresses TRAIL-induced apoptosis. Its expression, like the other three TRAIL receptors (i.e., DR4, DR5, and DcR1), is regulated by p53. Here, we report that DcR2 is a p53 target gene and regulates chemosensitivity. In this study, we identified a p53-binding site (p53BS) in the first intron of the DcR2 gene. This p53BS is almost identical to the ones found in the first introns of other three TRAIL receptor genes. By a chromatin immunoprecipitation assay, we detected that the p53 protein bound to the DcR2 p53BS in intact cells. Subcloning of the DcR2 p53BS into a luciferase reporter vector driven by a SV40 promoter exhibited enhanced luciferase activity when transiently cotransfected with a wild-type (wt) p53 expression vector in p53-null cell lines or stimulated with DNA-damaging agents in cell lines having wt p53. Moreover, when the DcR2 p53BS, together with its own corresponding promoter regions, was subcloned into a basic luciferase vector without a promoter element, its transcriptional activities were strikingly increased by cotransfection of the wt p53 gene. However, when this p53BS was deleted from the construct, wt p53 failed to transactivate this reporter construct. Collectively, we conclude that p53 directly regulates the DcR2 gene expression via an intronic p53BS. In addition, overexpression of DcR2 conferred resistance to TRAIL-mediated apoptosis and attenuated cell response to DNA-damaging agents, whereas silencing of DcR2 expression enhanced chemotherapeutic agent-induced apoptosis. These results suggest that DcR2 regulates chemosensitivity.

Preligand assembly domain-mediated ligand-independent association between TRAIL receptor 4 (TR4) and TR2 regulates TRAIL-induced apoptosis

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a cytokine with potential therapeutic value against cancers because of its selective cytotoxicity to many transformed, but not normal, cells. The "decoy receptors" TRAIL-R3 (TR3) and TRAIL-R4 (TR4) were believed to negatively regulate TRAIL-induced cytotoxicity by competing for ligand binding with TRAIL-R1 (TR1) and TRAIL-R2 (TR2). Here, we show that inhibition of TRAIL-induced apoptosis by TR4 critically depends on its association with TR2 via the NH(2)-terminal preligand assembly domain overlapping the first partial cysteine-rich domain of both receptors. By contrast, ligand binding by TR4 is dispensable for its apoptosis inhibitory function, thereby excluding the possibility that TR4 was a "decoy" to inhibit apoptosis by binding up TRAIL. In primary CD8(+) T cells, which express only TR2 and TR4 and are resistant to TRAIL-induced apoptosis, stimulation with phorbol myristate acetate abrogated the ligand-independent interaction between TR2 and TR4 and enhanced their sensitivity to TRAIL-induced apoptosis. Hence, whereas most TNF receptors normally form only homotrimeric complexes, the preligand assembly domains in TR2 and TR4 permit mixed complex formation as a means to regulate apoptosis induction. We propose that TR4 is a "regulatory" rather than "decoy" receptor that inhibits apoptosis signaling by TRAIL through this previously uncharacterized ligand-independent mechanism.

[TNF blockade in rheumatoid arthritis can cause severe fibrosing alveolitis. Six case reports]

TNF-blockade has been increasingly used in the treatment of rheumatoid arthritis (RA). However, the safety is unclear and an increased risk of both tuberculosis and other infections has been identified. Recently severe fibrosing alveolitis has also been reported in RA-patients treated with TNF-blockade. We report a further six RA patients, who during treatment with infliximab or etanercept developed fulminant lung fibrosis with alveolitis. For four of the patients, the fibrosing alveolitis was fatal. All patients were RF positive and above 60 years and five had mild fibrosis associated with RA before TNF-blockade treatment. Duration of TNF-blockade treatment was for three patients only two months and for the other three, 20-51 months. Age above 60 years and previous lung fibrosis appear to be risk factors for developing fibrosing alveolitis in RA patients treated with TNF-blockade.

[Increased risk of infection with biological immunomodifying antirheumatic agents. Clear guidelines are necessary as shown by case reports]

Several potent immunosuppressive drugs have become available in the new millennium for patients with rheumatologic diseases, Crohn's disease and other autoimmune disorders. Five patient cases from Växjö central hospital (uptake area 178 000 individuals) with Listeria meningitis, Pneumocystis jiroveci and tuberculosis pneumonia, Listeria sepsis, Legionella pneumonia and E coli sepsis are described. A doubled risk for infections has previously been observed for RA patients, as compared to healthy individuals. There is clearly an increased risk of tuberculosis (depending on the actual and historic environmental prevalence) for patients on TNF antagonists, and therefore tuberculosis screening is now mandatory before start of therapy. Since TNF has a central role in the immune defence, an increased risk of opportunistic infections like listeriosis. mycobacteriosis, and invasive fungal infections has been established. Eight hospitals in southern Sweden participate in a register for the use of TNF blockers in rheumatologic diseases (South Swedish Arthritis Treatment Group, SSATG). Guidelines for screening and treatment of latent and active tuberculosis, possible prophylactic antibiotic treatment for endocarditis and vaccination programs for patients on TNF antagonists are discussed.

Tumor necrosis factor alpha inhibitors and methotrexate: implications for deployed personnel

Rheumatic diseases such as rheumatoid and psoriatic arthritis are often diagnosed in younger age groups and are, therefore, likely to be encountered in active-duty military populations. These patients are increasingly being treated with disease modifying anti-rheumatic drugs (DMARDs) and biologic agents such as tumor necrosis factor alpha (TNF-alpha) inhibitors. While these classes of drugs have revolutionized the treatment of rheumatic diseases, they are also associated with serious potential adverse effects. At present, there are no published guidelines for the routine monitoring of laboratory parameters in patients receiving anti-TNF therapy. Currently, no official consensus among military physicians exists regarding duty and geographic limitations for patients receiving these types of therapy. Major adverse effects of these agents are reviewed in this article. A survey of U.S. Air Force, Army, and Navy rheumatologists was performed. The results of laboratory monitoring and operational deployment recommendations are reported. The majority of U.S. military rheumatologists do not recommend deployment of patients while taking methotrexate or TNF-alpha inhibitors.

Th1 cytokines are essential for placental immunity to Listeria monocytogenes

The fetal allograft poses an immunological challenge: how is it protected while immunity to pathogens, particularly those that replicate in the placenta, is maintained? Several theories have been proposed to explain this fetal protection, including a pregnancy-based bias towards a Th2 rather than Th1 cytokine profile in order to avoid generating cytotoxic T cells that could threaten the fetus. Listeria monocytogenes preferentially replicates in the placenta and systemically requires a Th1 response for sterile eradication. In the placenta, the Th1 cytokines tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma) are also synthesized in response to this pathogen, without fetal loss. Here we show, by using mice homozygous for null mutations in either the cytokine or cytokine receptor genes, a requirement for both TNF-alpha and IFN-gamma signaling for an effective placental immune response to L. monocytogenes. However, T cells were not recruited to the placenta. Genetic studies in which the fetal component of the placenta was genetically different from the mother indicated that both the production of and response to these cytokines were maternal. Despite the requirement for these cytokines, the early recruitment of neutrophils to the placenta was normal. Consequently, the bacterium appeared to be delayed in its colonization of this organ and did not fully gain hold until 72 h postinfection. These data show a requirement for Th1 cytokines during pregnancy for effective immunity and indicate that a bias away from Th1 cytokine synthesis is not a necessary prerequisite of pregnancy.

Mechanism for removal of tumor necrosis factor receptor 1 from the cell surface by the adenovirus RIDalpha/beta complex

Proteins encoded in adenovirus early region 3 have important immunoregulatory properties. We have recently shown that the E3-10.4K/14.5K (RIDalpha/beta) complex downregulates tumor necrosis factor receptor 1 (TNFR1) expression at the plasma membrane. To study the role of the RIDbeta tyrosine sorting motif in the removal of surface TNFR1, tyrosine 122 on RIDbeta was mutated to alanine or phenylalanine. Both RIDbeta mutations not only abolished the downregulation of surface TNFR1 but paradoxically increased surface TNFR1 levels. RID also downregulates other death receptors, such as FAS; however, surface FAS expression was not increased by RIDbeta mutants, suggesting that regulation of TNFR1 and that of FAS by RID are mechanistically different. In the mixing experiments, the wild-type (WT) RID-mediated TNFR1 downregulation was partially inhibited in the presence of RIDbeta mutants, indicating that the mutants compete for TNFR1 access. Indeed, an association between RIDbeta and TNFR1 was shown by coimmunoprecipitation. In contrast, the mutants did not affect the WT RID-induced downregulation of FAS. These differential effects support a model in which RID associates with TNFR1 on the plasma membrane, whereas RID probably associates with FAS in a cytoplasmic compartment. By using small interfering RNA against the mu2 subunit of adaptor protein 2, dominant negative dynamin construct K44A, and the lysosomotropic agents bafilomycin A1 and ammonium chloride, we also demonstrated that surface TNFR1 was internalized by RID by a clathrin-dependent process involving mu2 and dynamin, followed by degradation of TNFR1 via an endosomal/lysosomal pathway.

Modification of pro- and antiinflammatory cytokines and vascular-related molecules by tumor necrosis factor-a blockade in patients with rheumatoid arthritis

OBJECTIVE

Analysis of serum concentrations and modifications of tumor necrosis factor-a (TNF-a), its soluble receptors (TNFR), interleukin 10 (IL-10), and vascular related molecules [soluble vascular cell adhesion molecule 1 (sVCAM-1), vascular endothelial growth factor (VEGF)] after therapy with methotrexate (MTX) and anti-TNF (infliximab) in patients with rheumatoid arthritis (RA).

METHODS

Thirty-six patients with RA and 20 healthy controls were included. Patients had been orally taking a stable dose of MTX of at least 12.5 mg/week for a minimum of 6 months before inclusion in the study. Twenty-five patients had shown a clinical response to MTX (MTX Group). The other 11 had shown an unsatisfactory response and presented with active RA; they were selected for additional treatment with infliximab (MTX + IFM Group). Disease activity score (DAS28), hemoglobin concentration, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and serum levels of TNF-a, soluble TNFR, IL-10, sVCAM-1 and VEGF were determined at baseline and prior to every infusion of infliximab (3 mg/kg) at 2, 6, 14, 22, and 30 weeks.

RESULTS

Although serum levels of TNF-a were similar in patients and controls, patients showed significantly higher concentrations of both soluble TNFR (sTNFR55 and sTNFR75), IL-10, sVCAM-1, and VEGF than healthy individuals. Significantly higher levels of sVCAM-1 and VEGF, but not of the other tested molecules, were detected in those with active disease. After infliximab treatment (MTX + IFM Group) there was a significant decrease in DAS28 and modified Health Assessment Questionnaire scores and ESR and CRP levels. Serum concentration of VEGF showed a significant decrease after infliximab, with levels comparable to those of patients with inactive RA, although VEGF continued to present higher values than in healthy controls.

CONCLUSION

Increased levels of vascular related molecules sVCAM-1 and VEGF are serum markers of active RA. The absence of normalization of levels of these molecules in patients with inactive RA could be one of the reasons response to therapy is only temporary.

TNF-alpha-dependent and -independent maturation of dendritic cells and recruited CD11c(int)CD11b+ Cells during oral Salmonella infection

Maturation of dendritic cells (DC) is crucial for their ability to induce adaptive immunity. Although several mediators of DC maturation have been found, their contributions to DC maturation during infection are poorly understood. In this study we show that murine conventional (CD11c(high)) DC up-regulate costimulatory molecules in a subset-specific manner after oral Salmonella infection. Although both CD8alpha+ and CD8alpha- subsets increase CD86 expression, CD40 was preferentially up-regulated on CD8alpha+ DC, and CD80 was preferentially increased on CD8alpha- DC. In addition, high levels of CD80 and CD86 were found on CD11c(int)CD11b+ cells that accumulated in infected organs. Costimulatory molecules were simultaneously induced on CD11c(high) and CD11c(int)CD11b+ cells in Peyer's patches, mesenteric lymph nodes and spleen 5 days after infection despite different kinetics of peak bacterial burden in these organs. Up-regulation of costimulatory molecules occurred on all DC within the respective subset. Moreover, <1% of CD11c-expressing cells associated with Salmonella expressing enhanced GFP in vivo. Thus, DC maturation did not depend on bacterial uptake. Rather, infection-induced up-regulation of CD80, CD86, and CD40 on CD11c-expressing cells of mesenteric lymph nodes was dependent on TNFR type I (TNFRI) signaling. Although indirect up-regulation of costimulatory molecules on DC and CD11c(int)CD11b+ cells was TNFRI dependent, cells directly associated with Salmonella were able to mature independently of TNFRI signaling. Thus, Salmonella-induced TNF-alpha is an important mediator of indirect DC maturation during infection, whereas a TNF-alpha-independent maturation pathway contributes to direct maturation of bacteria-associated DC.