Overexpression of truncated I kappa B alpha potentiates TNF-alpha-induced apoptosis in mesangial cells

Synthesis and anticancer activity of some pyrimidine derivatives with aryl urea moieties as apoptosis-inducing agents

A new series of pyrimidine derivatives containing aryl urea moieties was designed and synthesized. The anticancer activities of all compounds were evaluated in vitro against colon and prostat cancer cell lines by MTT assay. Among these compounds, 4b exhibited the highest cytotoxic activity against SW480 cancer cell line with IC₅₀ value of 11.08 µM. Mechanistic studies showed that compound 4b arrested cell cycle at G2/M phase and induced apoptosis through upregulating Bax, Ikb-α and cleaved PARP and downregulating Bcl-2 expression levels. Moreover, compound 4b induced loss of mitochondrial membrane potential in SW480 cells. These results suggest that pyrimidine with urea moieties could be a template for designing new anticancer agents.

Renal Damaging Effect Elicited by Bicalutamide Therapy Uncovered Multiple Action Mechanisms As Evidenced by the Cell Model

Bicalutamide (Bic) is frequently used in androgen deprivation therapy (ADT) for treating prostate cancer. ADT-induced hypogonadism was reported to have the potential to lead to acute kidney injury (AKI). ADT was also shown to induce bladder fibrosis via induction of the transforming growth factor (TGF)-β level. We hypothesized that Bic can likely induce renal fibrosis. To understand this, a cell model was used to explore expressions of relevant profibrotic proteins. Results indicated that Bic initiated multiple apoptotic and fibrotic pathways, including androgen deprivation, downregulation of the androgen receptor → phosphatidylinositol-3-kinase → Akt pathway, upregulation of the extrinsic apoptotic pathway- tumor necrosis factor α →  nuclear factor κB → caspase-3, increased expressions of fibrosis-related proteins including platelet-derived growth factor β, fibronectin and collagen IV, and enhanced cell migration. The endoplasmic reticular stress pathway and smooth muscle actin were unaffected by Bic. Co-treatment with testosterone was shown to have an anti-apoptotic effect against Bic, suggesting a better outcome of Bic therapy if administered with an appropriate testosterone intervention. However, since Bic was found to inhibit the membrane transport and consumption rates of testosterone, a slightly larger dose of testosterone is recommended. In conclusion, these pathways can be considered to be pharmaceutically relevant targets for drug development in treating the adverse effects of Bic.

Basic helix-loop-helix transcriptional factor MyoR regulates BMP-7 in acute kidney injury

MyoR was originally identified as a transcriptional repressor in embryonic skeletal muscle precursors, but its function in adult kidney has not been clarified. In this study, we tried to clarify the functional role of MyoR using MyoR(-/-) mice. Cisplatin induced a significantly higher degree of severe renal dysfunction, tubular injury, and mortality in MyoR(-/-) mice than in wild-type mice. The injection of cisplatin significantly increased the number of apoptotic cells in the kidney tissues of MyoR(-/-) mice, compared with that in wild-type mice. To clarify the mechanism of severe cisplatin-induced damage and apoptosis in MyoR(-/-) mice, we focused on the p53 signaling pathway and bone morphogenic protein-7 (BMP-7). Treatment with cisplatin significantly activated p53 signaling in cultured renal proximal tubular epithelial cells (RTECs) in both wild-type and MyoR(-/-) mice, but no significant difference between the groups was observed. The injection of cisplatin significantly increased the expression of BMP-7 in the kidney tissues of wild-type mice, but no increase was observed in the MyoR(-/-) mice. Treatment with cisplatin significantly increased the expression of BMP-7 in cultured RTECs from wild-type mice but not in those from MyoR(-/-) mice. Moreover, treatment with recombinant BMP-7 rescued the cisplatin-induced apoptosis in RTECs from MyoR(-/-) mice. Taken together, our results demonstrate a new protective role of MyoR in adult kidneys that acts through the regulation of BMP-7.

Angiotensin II type I receptor agonistic autoantibody-induced apoptosis in neonatal rat cardiomyocytes is dependent on the generation of tumor necrosis factor-α

Angiotensin II type I receptor agonistic autoantibodies (AT1-AA) are related to pre-eclampsia and hypertension and have a direct effect of stimulating the production of tumor necrosis factor-alpha (TNF-α) in the placenta. TNF-α is a known mediator of apoptosis. However, few studies have reported the role of TNF-α and its relationship within AT1-AA-induced apoptosis of cardiomyocytes. In this study, neonatal rat cardiomyocytes were treated with various concentrations of AT1-AA. The apoptosis of neonatal rat cardiomyocytes was determined using TUNEL assay and flow cytometry. The level of secreted TNF-α was measured by enzyme-linked immunosorbent assay, and caspase-3 activity was measured by a fluorogenic protease assay kit. AT1 receptor blockade and TNF inhibitor were added to determine whether they could inhibit the apoptotic effect of AT1-AA. Results showed that AT1-AA induced the apoptosis of neonatal rat cardiomyocytes in a dose-dependent and time-dependent manner. AT1-AA increased TNF secretion and caspase-3 activities. AT1 receptor blockade completely abrogated AT1-AA-induced TNF-α secretion, caspase-3 activation, and cardiomyocyte apoptosis. TNF-α receptor inhibitor significantly attenuated AT1-AA-induced neonatal rat cardiomyocyte apoptosis. AT1-AA in the plasma of pre-eclamptic patients promoted neonatal rat cardiomyocyte apoptosis through a TNF-caspase signaling pathway.

Eicosapentaenoic acid regulates IκBα and prevents tubulointerstitial injury in kidney

Fish oil containing n-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is well known to prevent the progression of IgA nephropathy. However, the mechanism through which fish oil prevents the progression of renal injury remains uncertain. We tried to clarify the effects of EPA on tubulointerstitial injury in the kidney both in vivo and in vitro. We examined the effects of EPA, especially to focus on nuclear factor kappa B (NF-κB), using Thy-1 nephritis models. Also the mechanism of EPA was investigated using small-interfering RNA (siRNA) in lipopolysaccharide (LPS)-stimulated proximal tubular epithelial cells (PTECs). In Thy-1 nephritis models, EPA significantly inhibited tubulointerstitial injury and the infiltration of macrophages into tubulointerstitial lesions except severe glomerular injury at early stage. Compared with control animals, NF-κB activation was significantly augmented in the Thy-1 nephritic kidney. However, treatment with EPA significantly reduced NF-κB activation, down-regulated the expressions of NF-κB-dependent molecules. Also in LPS-stimulated PTECs, LPS augmented NF-κB activation and the expression of NF-κB-dependent molecules. As in the case with the Thy-1 nephritis models, treatment with EPA inhibited them, prevented the degradation of IκBα in LPS-stimulated PTECs. Pre-treatment with siRNA for IκBα abolished the inhibitory effect of EPA on LPS-induced NF-κB activation, suggesting that EPA inhibited NF-κB activation by regulating IκBα. Our results indicate that EPA prevents the early progression of tubulointerstitial injury in Thy-1 nephritis models, and the inhibitory effect of EPA on the expression of inflammatory molecules via the regulation of IκBα in cultured cells may explain this mechanism.

Anti-TNF-alpha therapies in systemic lupus erythematosus

Tumor necrosis factor (TNF)-α is not just a proinflammatory cytokine. It has also been proposed to be an immunoregulatory molecule that can alter the balance of T regulatory cells. Anti-TNF-α therapies have been provided clinical benefit to many patients and introduced for treating moderate to severe rheumatoid arthritis, Crohn's disease, and other chronic inflammatory disorders. However, their use also is accompanied by new or aggravated forms of autoimmunity, such as formation of autoantibodies, including antinuclear antibodies (ANAs), antidouble-stranded DNA (dsDNA) antibodies, and anticardiolipin antibodies (ACL). Systemic lupus erythematosus (SLE) is a disease with autoimmune disturbance and inflammatory damage. The role of TNF-α in human SLE is controversial. Here we review the role of TNF-α in the pathophysiological processes of SLE and the likely effects of blocking TNF-α in treatment of SLE.

TNF induces caspase-dependent inflammation in renal endothelial cells through a Rho- and myosin light chain kinase-dependent mechanism

The pathogenesis of LPS-induced acute kidney injury (AKI) requires signaling through tumor necrosis factor-alpha (TNF) receptor 1 (TNFR1), which within the kidney is primarily located in the endothelium. We showed previously that caspase inhibition protected mice against LPS-induced AKI and in parallel significantly inhibited LPS-induced renal inflammation. Therefore we hypothesized that caspase activation amplifies TNF-induced inflammation in renal endothelial cells (ECs). In cultured renal ECs, TNF induced apoptosis through a caspase-8-dependent pathway. TNF caused translocation of the p65 subunit of NF-kappaB to the nucleus, resulting in upregulation of inflammatory markers such as adhesion molecules ICAM-1 and VCAM-1. However, the broad-spectrum caspase inhibitor Boc-d-fmk reduced NF-kB activation as assessed by gel shift assay, reduced phosphorylation of subunit IkappaBalpha, and significantly inhibited TNF-induced expression of ICAM-1 and VCAM-1 as assessed by both real-time PCR and flow cytometry. Broad-spectrum caspase inhibition markedly inhibited neutrophil adherence to the TNF-activated endothelial monolayer, supporting the functional significance of this effect. Specific inhibitors of caspases-8 and -3, but not of caspase-1, reduced TNF-induced NF-kappaB activation. Caspase inhibition also reduced TNF-induced myosin light chain (MLC)-2 phosphorylation, and activation of upstream regulator RhoA. Consistent with this, MLC kinase (MLCK) inhibitor ML-7 reduced TNF-induced NF-kappaB activation. Thus caspase activation influences NF-kappaB signaling via its affect on cytoskeletal changes occurring through RhoA and MLCK pathways. These cell culture experiments support a role for caspase activation in TNF-induced inflammation in the renal endothelium, a key event in LPS-induced AKI.

Inhibition of NF-kappaB-dependent Bcl-xL expression by clusterin promotes albumin-induced tubular cell apoptosis

Apoptosis and inflammation, important contributors to the progression of chronic kidney disease, can be influenced by clusterin (a secreted glycoprotein that regulates apoptosis) and nuclear factor-kappaB (NF-kappaB, a transcription factor modifying the expression of inflammatory genes). We studied proteinuria-induced renal disease and its influence on clusterin-mediated apoptosis. Exposure of cultured mouse proximal tubule epithelial cells to bovine serum albumin (BSA) resulted in activation of NF-kappaB and activator protein-1 (AP-1) within hours followed by a decline in their activation, decreased activation of extracellular signal-regulated kinases (ERK1/2), decreased cell-associated antiapoptotic Bcl-xL protein but increased apoptosis. Clusterin progressively increased in the media over a 3 day period. Clusterin siRNA blocked protein production, increased NF-kappaB activation, and significantly increased cellular Bcl-xL protein, thereby reducing spontaneous and BSA-induced apoptosis. An siRNA to the NF-kappaB inhibitor IkappaBalpha had similar results. BSA-stimulated NF-kappaB activation reciprocally decreased AP-1 activity by preventing ERK1/2 phosphorylation. These in vitro studies suggest that clusterin inhibits NF-kappaB-mediated antiapoptotic effects by the apparent stabilization of IkappaBalpha switching from promoting inflammation to apoptosis during proteinuria.

Mediators of fibrosis and apoptosis in obstructive uropathies

Upper urinary tract obstruction, regardless of its cause, often poses a significant clinical challenge to the urologist. Renal cellular and molecular events that occur in response to upper urinary tract obstruction result in a progressive and permanent loss in renal function when left untreated. These pathologic changes include the development of renal fibrosis, tubular atrophy, interstitial inflammation, and apoptotic renal cell death. Several cytokines and growth factors have been identified as major contributors to obstruction-induced renal fibrosis and apoptotic cell death, most notably transforming growth factor-b1 (TGF-b1), angiotensin II, nuclear factor-kB (NF-kB), and tumor necrosis factor-a (TNF-a). This review examines the challenges of upper urinary tract obstruction and the role of these mediators in obstruction-induced renal injury.

Roles of NF-κB and Bcl-2 in Two Differential Modes of Cell Death of Mouse Cortical Collecting Duct Cells

Recent data have implicated nuclear factor-kappaB (NF-kappaB) and Bcl-2 in the regulation of apoptotic and necrotic cell death in various cells. However, mechanisms of their effects on cell death of renal epithelial cells are not clear. First, we investigated the effect of specific inhibition of NF-kappaB and overexpression of Bcl-2 on necrotic cell death induced by hydrogen peroxide or cisplatin in renal collecting duct cells. M-1 cells, which were derived from outer cortical collecting duct, were stably transfected with the non-phosphorylatable mutant of inhibitory-kappaBalpha (I-kappaBalpha) and Bcl-2. Overexpression of I-kappaBalpha and Bcl-2 did not affect cisplatin-induced necrotic cell death, but overexpression of I-kappaBalpha significantly decreased H2O2-induced cell death. Regarding apoptotic cell death induced by cisplatin, serum deprivation and contact inhibition was increased by overexpression of I-kappaBalpha, whereas overexpression of bcl-2 inhibited the apoptotic cell death. I-kappaBalpha overexpression increased Bax expression and decreased cIAP-1 and -2 expression compared to vector-transfected cells, but did not alter SAPK/JNK activity in the presence or absence of cisplatin. NF-kappaB activity was significantly higher in bcl-2-overexpressing cells than in control cells. These data show that activation of NF-kappaB mediates H2O2-induced necrotic injury, but inhibits apoptotic cell death in renal collecting duct cells, and that Bcl-2 selectively protects apoptotic cell death in M-1 cells.

Inhibition of NF-kappaB renders human juvenile costal chondrocyte cell lines sensitive to TNF-alpha-mediated cell death

BACKGROUND

Recently, therapeutics employing knowledge on various signaling pathways are being developed, with NF-kappaB being one of the most promising targets. NF-kappaB has been suggested to play a role not only in the induction of inflammatory mediators, but also in the protection from cell death.

OBJECTIVES

This study pursued the role of the NF-kappaB pathway in the regulation of chondrocyte death induced by tumor necrosis factor alpha (TNF-alpha) and of the pertinent target molecules involved.

METHODS

The human chondrocyte cell line C28/I2 was used for the experiment. Chondrocytes were transduced with adenovirus-encoding IkappaB (IkappaB) superrepressor which inhibits NF-kappaB activation, and treated with TNF-alpha. The proportion of cell death was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazdium bromide (MTT) assay. Activation of p38 mitogen activated protein (MAP) kinase and phosphatidylinositol 3-kinase (PI3K) by TNF-alpha was inhibited with SB202190 and Ly 294002 respectively. The expression of apoptosis related protein was analyzed with western blot assay, and the activation of c-Jun N-terminal kinase (JNK) by solid-phase kinase assay.

RESULTS

Treatment with TNF-alpha led to cell death in 23% and 50% of ad-IkappaB-SR infected chondrocytes after 24 and 72 h respectively. The expression of Bcl-XL, Bcl-2, and XIAP significantly decreased, and activation of JNK was prolonged for up to 6 h in infected cells treated with TNF-alpha. Preincubation with p38 inhibitor or PI3K inhibitor before TNF-alpha led to a significant increase in cell death in ad-IkappaB-SR transduced chondrocytes, resulting in 53% and 30% cell death after 24 h for p38 inhibitor and PI3K inhibitor respectively.

CONCLUSION

In our experimental system, specific inhibition of NF-kappaB activation rendered chondrocytes susceptible to cell death induced by TNF-alpha. The cell death was enhanced by inhibition of another signaling pathway such as p38 MAP kinase or PI3K. The expression of Bcl-XL, Bcl-2 and XIAP and activation of JNK were affected by ad-IkappaB-SR transduction, implying a role in the NF-kappaB regulated cell survival signaling in human chondrocytes.

Inflammatory mediators and growth factors in obstructive renal injury

Obstruction of the upper urinary tract poses a significant clinical challenge to the urologist, and the cascade of renal cellular and molecular events triggered by upper urinary tract obstruction result in a progressive, and eventually permanent, loss in renal function. These pathological changes include the development of renal fibrosis, tubular atrophy, interstitial inflammation, and apoptotic renal cell death. A myriad of cytokines and growth factors have been identified as major contributors to obstruction-induced renal fibrosis and apoptotic cell death, including transforming growth factor-beta1, angiotensin II, nuclear factor-kappaB, and tumor necrosis factor-alpha. This review examines the role of these mediators in obstruction-induced renal injury.

Caffeic acid phenethyl ester induces apoptosis by inhibition of NFkappaB and activation of Fas in human breast cancer MCF-7 cells

The transcription factor NFkappaB plays a role in cell survival. Apoptosis, programmed cell death, via numerous triggers including death receptor ligand binding is antagonized by NFkappaB activation and potentiated by its inhibition. In the present study, we found that caffeic acid phenethyl ester (CAPE), known to inhibit NFkappaB, induced apoptosis via Fas signal activation in human breast cancer MCF-7 cells. CAPE activated Fas by a Fas ligand (Fas-L)-independent mechanism, induced p53-regulated Bax protein, and activated caspases. CAPE also activated MAPK family proteins p38 and JNK. SB203580, a specific inhibitor of p38 MAPK, partially suppressed CAPE-induced p53 activation, Bax expression, and apoptosis, consistent with a mechanism by which CAPE leads to Bax activation, known to be regulated by p38 and p53. The expression of dominant negative c-Jun, which inhibits the JNK signal, also suppresses CAPE-induced apoptosis, suggesting MAPKs are involved in CAPE-induced apoptosis. The expression of Fas antisense oligomers significantly suppressed the CAPE-induced activations of JNK and p38 and apoptosis as compared with Fas sense oligomers. To ascertain whether these phenomena are attributable to the inhibition of NFkappaB by CAPE, we examined the effect of a truncated form of IkappaBalpha (IkappaBDeltaN) lacking the phosphorylation sites essential for NFkappaB activation. IkappaBDeltaN expression not only inhibited NFkappaB activity but also induced Fas activation, Bax expression, and apoptosis. Our findings demonstrate that NFkappaB inhibition is sufficient to induce apoptosis and that Fas activation plays a role in NFkappaB inhibition-induced apoptosis in MCF-7 cells.

Cyclooxygenase-2 inhibits tumor necrosis factor alpha-mediated apoptosis in renal glomerular mesangial cells

Renal mesangial cell apoptosis is a crucial repair mechanism in glomerular nephritis (GN). These cells express receptors to tumor necrosis factor alpha (TNFalpha), a cytokine with proapoptotic properties implicated in the resolution of GN. Progression to proliferative GN is accompanied by cyclooxygenase-mediated formation of prostaglandins and inefficient apoptosis of mesangial cells. The aims of this study were to quantify TNFalpha-mediated apoptosis in renal mesangial cells and to determine whether expression of the inducible form of cyclooxygenase, cylooxygenase-2 (COX-2), inhibits this apoptosis. By 24 h significant levels of apoptosis were induced by TNFalpha (100 ng/ml) or etoposide control (100 microm), as shown by phosphatidylserine externalization, caspase-3 activation, development of a sub-G(0)/G(1) region, and distinct chromatin condensation. Using adenoviral-mediated delivery of the COX-2 gene (AdCOX-2) apoptotic features were prevented from appearing in AdCOX-2 cells treated with TNFalpha, whereas etoposide-treated AdCOX-2 cells were not protected. Furthermore, COX-2 expression, induced by the vasoconstrictor peptide ET-1 or the cytokine interleukin-1beta also inhibited TNFalpha-mediated but not etoposide-mediated apoptosis, to an extent, similar to adenoviral COX-2 infection. Selective COX-2 inhibition by NS-398 restored TNFalpha-mediated apoptosis. Prostaglandin (PG) E(2) and PGI(2) were shown to be the major prostaglandin metabolites in AdCOX-2 cells. The addition of PGE(2) and PGI(2) protected against TNFalpha-mediated apoptosis. These results demonstrate COX-2 anti-apoptotic activity via a death receptor route and suggest that selective COX-2 inhibition may augment TNFalpha apoptosis in chronic inflammatory conditions.

Liposomal delivery of heat shock protein 72 into renal tubular cells blocks nuclear factor-kappaB activation, tumor necrosis factor-alpha production, and subsequent ischemia-induced apoptosis

Heat shock protein 72 (HSP72) is a stress-inducible protein capable of protecting a variety of cells from toxins, thermal stress, and ischemic injury. The cytoprotective role and mechanism of action of HSP72 in renal cell ischemic injury remain unclear. To study this, HSP72 was introduced (liposomal transfer) or induced (thermal stress, 43 degrees Cx1 hour) in renal tubular cells (LLC-PK1) with Western blot confirmation. Cells were subjected to simulated ischemia 24 hours after liposomal HSP72 transfer or thermal stress, and the effect of HSP72 on nuclear factor-kappaB (NF-kappaB) activation (electrophoretic mobility shift assay and immunohistochemistry), IkappaBalpha production (Western blot), postischemic tumor necrosis factor-alpha (TNF-alpha) production (RT-PCR), and apoptosis (TUNEL assay) were determined. In separate experiments, the role of TNF-alpha in apoptosis was determined (anti-TNF-alpha neutralizing antibody). Results demonstrated that both liposomal transfer of HSP72 and thermal induction of HSP72 prevented NF-kappaB activation and translocation, TNF-alpha gene transcription, and subsequent ischemia-induced renal tubular cell apoptosis. Furthermore, TNF-alpha neutralization also inhibited ischemia-induced renal tubular cell apoptosis. These results indicate that liposomal delivery of HSP72 inhibits ischemia-induced renal tubular cell apoptosis by preventing NF-kappaB activation and subsequent TNF-alpha production. Further elucidation of the mechanisms of HSP-induced cytoprotection may result in therapeutic strategies that limit or prevent ischemia-induced renal damage.

Gene transfer of truncated IkappaBalpha prevents tubulointerstitial injury

BACKGROUND

Severe proteinuria not only indicates the presence of progressive glomerular disease, but also causes tubular epithelial cells to produce inflammatory mediators leading to tubulointerstitial (TI) injury. We investigated the role of nuclear factor-kappaB (NF-kappaB) in tubular epithelial cells in the development of proteinuria-induced TI injury.

METHODS

To specifically inhibit NF-kappaB activation, a recombinant adenovirus vector expressing a truncated form of IkappaBalpha (AdexIkappaBDeltaN) was injected into renal arteries of protein-overloaded rats, a model of TI injury characterized by infiltration of mononuclear cells and fibrosis.

RESULTS

Activation of NF-kappaB in the renal cortex, observed in protein-overloaded rats treated with a control vector, recombinant lacZ adenovirus, was prevented in AdexIkappaBDeltaN-injected rats. Microscopic examination revealed AdexIkappaBDeltaN treatment to markedly attenuate proteinuria-induced TI injury. Increased immunostaining of vascular cell adhesion molecule-1, transforming growth factor-beta, and fibronectin in TI lesions also was suppressed by AdexIkappaBDeltaN injection.

CONCLUSIONS

These findings provide evidence of the critical role of NF-kappaB activation in TI injury and suggest the therapeutic potential of adenovirus-mediated IkappaBDeltaN gene transfer into the kidney as a means of interrupting the process of TI damage.

Role of NF-kappaB on liver cold ischemia-reperfusion injury

The role of NF-kappaB, the rapid-response transcription factor for multiple genes, in cold ischemia-reperfusion (I/R) injury was examined after syngeneic transplantation of liver grafts. Lewis rat recipients were killed 1-48 h after reperfusion of three different liver grafts: 1) uninfected control, 2) infected ex vivo with control adenoviral vector (AdEGFP), and 3) infected ex vivo with AdIkappaB. In uninfected control livers, NF-kappaB was activated biphasically at 1-3 and 12 h after reperfusion with aspartate transaminase (AST) levels of 4,244 +/- 691 IU/l. The first peak of NF-kappaB activation associated with an increase of mRNA for TNF-alpha, IL-1beta, and IL-10. AdEGFP transfection resulted in similar outcomes. Interestingly, AdIkappaB-transfected liver grafts suffered more severe I/R injury (AST >9,000 IU/l). Transfected IkappaB was detected in transplanted livers as early as 6 h, and this correlated with the abrogation of the second, but not the first, peak of NF-kappaB activation at 12-48 h and increased apoptosis. Thus inhibition of the second wave of NF-kappaB activation in IkappaB-transfected livers resulted in an increase of liver injury, suggesting that NF-kappaB may have a dual role during liver I/R injury.

Role of TNF/TNFR in autoimmunity: specific TNF receptor blockade may be advantageous to anti-TNF treatments

Deregulated TNF production, be it low or high, characterizes many autoimmune diseases. Recent evidence supports a dualistic, pro-inflammatory and immune- or disease-suppressive role for TNF in these conditions. Blocking TNF in autoimmune-prone chronic inflammatory diseases may, therefore, lead to unpredictable outcomes, depending on timing and duration of treatment. Indeed, blockade of TNF in human rheumatoid arthritis or inflammatory bowel disease patients, although so far impressively beneficial for the majority of patients, it has also led to a significant incidence of drug induced anti-dsDNA production or even in manifestations of lupus and neuro-inflammatory disease. Notably, anti-TNF treatment of multiple sclerosis patients has led almost exclusively to immune activation and disease exacerbation. We discuss here recent evidence in murine disease models, indicating an heterogeneity of TNF receptor usage in autoimmune suppression versus inflammatory tissue damage, and put forward a rationale for a predictably beneficial effect of 'anti-TNFR' instead of 'anti-TNF' treatment in human chronic inflammatory and autoimmune conditions.

Tranilast inhibits interleukin-1beta-induced monocyte chemoattractant protein-1 expression in rat mesangial cells

Monocyte chemoattractant protein-1 (MCP-1), a member of the CC subfamily of chemokines, plays a crucial role in the progression of glomerulonephritis by recruitment of monocytes. Tranilast, a clinically used anti-allergic drug, has been demonstrated to have various anti-inflammatory and anti-proliferative effects, and recently has been reported to prevent restenosis after percutaneous transluminal coronary angioplasty. In this study, we investigated whether tranilast inhibits MCP-1 secretion in mesangial cells. Tranilast inhibited interleukin-1beta-induced MCP-1 secretion and mRNA expression in a concentration-dependent manner. Luciferase assay showed that tranilast suppressed interleukin-1beta-induced nuclear factor-kappaB (NF-kappaB)-dependent transcription. Interleukin-1beta-induced Jun N-terminal kinase (JNK) activation was also suppressed selectively by tranilast. These results indicate that tranilast inhibits interleukin-1beta-induced MCP-1 production, at least in part, by inhibiting NF-kappaB activity and that suppression of JNK activation might be involved in the inhibition of MCP-1 production. Tranilast may serve as a new therapeutic agent for glomerulonephritis through anti-chemokine property.

[NF-kappa B as a therapeutic drug target]

The transcription factor NF-kappa B has attracted widespread interest based on its unusual regulation, the variety of stimuli that activate it, the diverse genes and biological responses that it controls, the striking evolutionary conservation of structure and function among family members, and its apparent involvement in a variety of human diseases. Recently NF-kappa B has been shown to be the target of new drug discovery. Here, we discuss the so-called NF-kappa B inhibitors and consider the development of new therapeutic agents.

Static pressure regulates connective tissue growth factor expression in human mesangial cells

Connective tissue growth factor (CTGF) is overexpressed in a variety of fibrotic disorders such as renal fibrosis and atherosclerosis. Fibrosis is a common final pathway of renal diseases of diverse etiology, including inflammation, hemodynamics, and metabolic injury. Mechanical strains such as stretch, shear stress, and static pressure are possible regulatory elements in CTGF expression. In this study, we examined the ability of static pressure to modulate CTGF gene expression in cultured human mesangial cells. Low static pressure (40-80 mm Hg) stimulated cell proliferation via a protein kinase C-dependent pathway. In contrast, high static pressure (100-180 mm Hg) induced apoptosis in human mesangial cells. This effect was reversed by treatment with CTGF antisense oligonucleotide but not with transforming growth factor beta1-neutralizing antibody or protein kinase C inhibitor. High static pressure not only up-regulated the expression of CTGF, but also the expression of extracellular matrix proteins (collagen I and IV, laminin). This up-regulation of extracellular matrix proteins was also reversed by treatment with CTGF antisense oligonucleotide. As judged by mRNA expression of a total of 1100 genes, including apoptosis-associated genes using DNA microarray techniques, recombinant CTGF protein induced apoptosis by down-regulation of a number of anti-apoptotic genes. Overexpression of CTGF in mesangial cells by transient transfection had similar effects. Taken together, these results suggest that high blood pressure up-regulates CTGF expression in mesangial cells. High levels of CTGF in turn enhance extracellular matrix production and induce apoptosis in mesangial cells, and may contribute to remodeling of mesangium and ultimately glomerulosclerosis.

Overexpression of truncated IkappaBalpha induces TNF-alpha-dependent apoptosis in human vascular smooth muscle cells

Dysregulation of apoptosis is one of the likely underlying mechanisms of neointimal thickening, a disorder in which proinflammatory cytokines may influence the function of vascular smooth muscle cells (VSMCs) and contribute to atherogenesis. One of these cytokines, tumor necrosis factor-alpha (TNF-alpha), induces 2 possibly conflicting pathways, 1 leading to the activation of nuclear factor-kappaB (NF-kappaB) and the other leading to caspase-mediated apoptosis. We investigated whether specific inhibition of NF-kappaB affects TNF-alpha-dependent apoptosis in human VSMCs. To inhibit NF-kappaB activation specifically, we constructed a recombinant adenovirus vector expressing a truncated form of the inhibitor protein IkappaBalpha (AdexIkappaBDeltaN) that lacks the phosphorylation sites essential for activation of NF-kappaB. The IkappaBDeltaN was overexpressed by adenoviral infection and was resistant to stimulus-dependent degradation. Electromobility gel shift and luciferase assays demonstrated that overexpression of IkappaBDeltaN inhibited NF-kappaB activation induced by TNF-alpha or interleukin-1beta (IL-1beta). In cells overexpressing IkappaBDeltaN, TNF-alpha dramatically induced apoptosis, whereas IL-1beta had no effect. The induction was suppressed by treatment with a selective inhibitor of the caspase-3 family, Z-DEVD-fmk, and the overexpression of IkappaBDeltaN induced TNF-alpha-mediated caspase-3 and caspase-2 activity. These results indicate that overexpression of IkappaBDeltaN induces TNF-alpha-dependent apoptosis by efficient and specific suppression of NF-kappaB and upregulation of caspase-3 and caspase-2 activity in human VSMCs. Our findings suggest that adenovirus-mediated IkappaBDeltaN gene transfer may be useful in the treatment of disorders associated with inflammatory conditions, such as the response to vascular injury and atherosclerosis.

Genomic organization and immune regulation of the defensin gene from the mosquito, Anopheles gambiae

The defensin gene from the mosquito, Anopheles gambiae, is present as a single copy per haploid genome. Two exons, encoding a 102 residue preprodefensin, are separated by a 105 bp intron bounded by consensus splice sites. The upstream regulatory sequence includes a TATA box, arthropod initiator and numerous motifs homologous to insect and mammalian immune response elements. This promoter is capable of upregulation by immune challenge in cultured cells and activity is further stimulated by Gambif1, a mosquito Rel protein known to translocate to the nucleus and bind NF-kappa B sites in target promoters. Activity is inhibited by p50, a mammalian Rel protein that competitively binds NF-kappa B sites, and virtually abolished by p40, an avian I kappa B protein that inhibits nuclear translocation.