Antisense oligonucleotides to poly(ADP-ribose) polymerase-2 ameliorate colitis in interleukin-10-deficient mice

poly(ADP-ribose) polymerase-2 (PARP-2) is a newly described member of the PARP family of nuclear enzymes. Previous studies have shown pharmacological inhibition of PARP activity to have a beneficial role in attenuating inflammation. We developed a chemically modified 2'-O-(2-methoxy)ethyl antisense oligonucleotide (ISIS 110251) inhibitor of PARP-2 and tested it for efficacy in the interleukin (IL)-10-deficient mouse. In tissue culture, ISIS 110251 reduced PARP-2 mRNA expression in a concentration- and sequence-specific manner. In 129 Sv/Ev mice, ISIS 110251 reduced PARP-2 mRNA in liver by 80%. This reduction was dependent upon treatment duration and was independent of the method of delivery. In interleukin-10-deficient mice with established colitis, treatment with ISIS 110251 normalized colonic epithelial barrier and transport function, reduced proinflammatory cytokine secretion and inducible nitric-oxide synthase activity, and attenuated inflammation. Our data demonstrate that selective inhibition of PARP-2 activity results in a marked improvement of colonic inflammatory disease in a mouse model of chronic colitis and a normalization of colonic function.     

Hematopoietic stem cell functional failure in interleukin-2-deficient mice

The effects of interleukin-2 (IL-2) deficiency on hematopoiesis were tested by measuring cellular compositions in peripheral blood, spleen, thymus, and bone marrow of 3- to 5-month-old gene-targeted Il2 null (Il2(-/-)) mice using the Advia 120 Hematology system and fluorescence-activated cell staining (FACS). Il2(-/-) mice developed hematological failure and autoimmune responses, showing variable but significant degrees of anemia, lymphocytopenia, thrombocytopenia, splenomegaly, thymus involution, and weight loss. Surprisingly, Il2(-/-) mice had normal numbers of bone marrow cells (BMCs) with increased numbers of Lin(-)Kit(+)Sca1(+)CD34(-) and Lin(-)Kit(+)Sca1(+)CD34(+) cells that are normally associated with hematopoietic stem cells (HSCs) and progenitor cells. Day-12 colony-forming units-spleen cells were slightly reduced in Il2(-/-) mice. When Il2(-/-) and Il2(+/+) mice were compared for long-term HSC function in vivo in the competitive repopulation assay, BMCs from Il2(-/-) donors had 10- to 20-fold less HSC repopulating ability, which affected both myeloid and lymphoid cell lineages. Thus, HSCs from Il2(-/-) mice can proliferate normally but are functionally defective for reconstituting lethally irradiated recipients.     

4-hydroxynonenal decreases interleukin-6 expression and protein production in primary rat Kupffer cells by inhibiting nuclear factor-kappaB activation

Kupffer cells have been documented to play an important role in the early events of liver injury and regeneration by releasing biologically active mediators such as interleukin-6 (IL-6). 4-Hydroxy-trans-2-nonenal (4-HNE), a major end product of lipid peroxidation, has multiple cytotoxic effects and is implicated in chemical-induced liver injury. Consequently, the purpose of this study was to evaluate the ability of 4-HNE to modulate IL-6 production in isolated primary rat Kupffer cells. 4-HNE (0.1-10 microM) reduced both lipopolysaccharide (LPS)-induced IL-6 protein production and mRNA levels. The role of nuclear factor-kappaB (NF-kappaB) in IL-6 induction was elucidated using Kupffer cells transduced in vitro with a recombinant adenovirus containing a IkappaBalpha super-repressor resistant to phosphorylation and degradation (Ad5IkappaB). Using this system, LPS-induced IL-6 protein production was inhibited by 65% in Ad5IkappaB-infected cells. The treatment of Kupffer cells for 1 h with 4-HNE followed by stimulation for 1 h with LPS (500 ng/ml) resulted in a concentration-dependent decrease in NF-kappaB activation. Similarly, decreased NF-kappaB activity in these cells paralleled a reduction in IkappaBalpha mRNA levels. Furthermore, upon LPS stimulation, 4-HNE stabilized IkappaBalpha, which corresponded to a decrease in phosphorylated IkappaBalpha. At lower 4-HNE concentrations (0-5 microM), interactions between p65 and IkappaBalpha proteins were maintained as detected by immunoprecipitation-immunoblot analyses. In conclusion, these data suggest that 4-HNE inhibits IL-6 production in rat Kupffer cells by preventing activation of the NF-kappaB pathway and suppressing IkappaBalpha phosphorylation. These results have functional implications in that 4-HNE may interfere with the ability of Kupffer cells to produce cytokines proposed to play an important role in liver regeneration.     

Increased catecholamine secretion contributes to hypertension in TRPM4-deficient mice

Hypertension is an underlying risk factor for cardiovascular disease. Despite this, its pathogenesis remains unknown in most cases. Recently, the transient receptor potential (TRP) channel family was associated with the development of several cardiovascular diseases linked to hypertension. The melastatin TRP channels TRPM4 and TRPM5 have distinct properties within the TRP channel family: they form nonselective cation channels activated by intracellular calcium ions. Here we report the identification of TRPM4 proteins in endothelial cells, heart, kidney, and chromaffin cells from the adrenal gland, suggesting that they have a role in the cardiovascular system. Consistent with this hypothesis, Trpm4 gene deletion in mice altered long-term regulation of blood pressure toward hypertensive levels. No changes in locomotor activity, renin-angiotensin system function, electrolyte and fluid balance, vascular contractility, and cardiac contractility under basal conditions were observed. By contrast, inhibition of ganglionic transmission with either hexamethonium or prazosin abolished the difference in blood pressure between Trpm4^–/– and wild-type mice. Strikingly, plasma epinephrine concentration as well as urinary excretion of catecholamine metabolites were substantially elevated in Trpm4^–/– mice. In freshly isolated chromaffin cells, lack of TRPM4 was shown to cause markedly more acetylcholine-induced exocytotic release events, while neither cytosolic calcium concentration, size, nor density of vesicles were different. We therefore conclude that TRPM4 proteins limit catecholamine release from chromaffin cells and that this contributes to increased sympathetic tone and hypertension.     

Effect of corticosteroids on nuclear factor-kappaB activation and hemodynamics in late septic shock

OBJECTIVE: To describe the underlying pathophysiologic mechanisms of the effect of corticosteroids in a patient with late septic shock. DESIGN: Case report. SETTING: The medical intensive care unit at University Medical Center Utrecht. PATIENT: An 86-yr-old female patient with late septic shock requiring mechanical ventilation and vasopressive agents. INTERVENTIONS: Administration of hydrocortisone, 300 mg daily. MEASUREMENTS AND MAIN RESULTS: Within 3 days of corticosteroid treatment, the patient could be weaned of vasopressive agents and mechanical ventilation. Serum C-reactive protein levels normalized. Nuclear factor-kappaB activation in unstimulated and in vitro lipopolysaccharide-stimulated peripheral blood mononuclear cells decreased to background level within 5 days. Repeated functional tests of the hypothalamic-pituitary-adrenal axis were normal. CONCLUSION: Our data suggest that the pathophysiologic mechanism behind the clinical effects of supraphysiologic doses of corticosteroids in late septic shock is directly related to the inhibition of nuclear factor-kappaB in peripheral blood mononuclear cells.     

Caffeic acid phenethyl ester, an inhibitor of nuclear factor-kappaB, attenuates bacterial peptidoglycan polysaccharide-induced colitis in rats.

Caffeic acid phenethyl ester (CAPE) is an anti-inflammatory component of propolis (honeybee resin). CAPE is reportedly a specific inhibitor of nuclear factor-kappaB (NF-kappaB). The aims of our study were 1) to evaluate the effect of CAPE on cytokine production, NF-kappaB, and apoptosis in two cell lines; 2) to assess the effect of CAPE on NF-kappaB in rats with peptidoglycan-polysaccharide (PG-PS)-induced colitis; and 3) to evaluate the efficacy of CAPE against this colitis. In vitro experiments used rat macrophage (NR8383) and colonic epithelial cell (SW620) lines. NF-kappaB was evaluated by electrophoretic mobility shift assay. Cytokines and apoptosis were measured by enzyme-linked immunosorbent assay. Colitis was induced by intramural injections of PG-PS into the distal colon. CAPE (30 mg/kg) or vehicle was administered once daily to rats by intraperitoneal injection, for 1 week. Various macroscopic and biochemical indices were measured on day 21. CAPE (30 microg/ml) significantly inhibited NF-kappaB and TNF-alpha production in the macrophage cell line. In macrophages, CAPE significantly increased DNA fragmentation. CAPE exhibited generally similar effects in the colonic epithelial cell line. CAPE treatment reduced the mean level of colonic NF-kappaB in rats. CAPE also induced a significant reduction in gross colonic injury. Moreover, colonic cytokine levels (TNF-alpha and IL-1beta) were significantly reduced in CAPE-treated rats. In summary, CAPE inhibits NF-kappaB, causes a reduction of pro-inflammatory cytokine production, and induces apoptosis in macrophages. These mechanisms likely contributed to the attenuation of PG-PS-induced colitis by CAPE.     

Increased severity of local and systemic anaphylactic reactions in gp49B1-deficient mice.

gp49B1 is an immunoglobulin (Ig) superfamily member that inhibits FcstraightepsilonRI-induced mast cell activation when the two receptors are coligated with antibodies in vitro. The critical question of in vivo function of gp49B1 is now addressed in gene-disrupted mice. gp49B1-deficient mice exhibited a significantly increased sensitivity to IgE-dependent passive cutaneous anaphylaxis as assessed by greater tissue swelling and mast cell degranulation in situ. Importantly, by the same criteria, the absence of gp49B1 also resulted in a lower threshold for antigen challenge in active cutaneous anaphylaxis, in which the antigen-specific antibody levels were comparable in gp49B1-deficient and sufficient mice. Moreover, the absence of gp49B1 resulted in a significantly greater and faster death rate in active systemic anaphylaxis. These results indicate that gp49B1 innately dampens adaptive immediate hypersensitivity responses by suppressing mast cell activation in vivo. In addition, this study provides a new concept and target for regulation of allergic disease susceptibility and severity.     

白介素—10对内毒素诱导肺泡巨噬细胞核因子—kB活化及肿瘤坏死因子释放的调节

目的 探讨白介素－10对内毒素（LPS）诱导肺泡巨噬细胞核因子－kB(NF-kB）活伦及肿瘤坏死因子α（TNF-α)基因表达的调节,为临床运用白介素－10提供理论依据。方法 用支气管肺泡灌洗法收集肺巨噬细胞（PAM）进行培养,分正常对照组、LPS 、IL－10＋LPS组。用凝胶电泳迁移率改变分析（EMSA）法和ELIS法分别检测核提取物中NF－kB活性和细胞培养上清中TNF－α含量。结果 LPS组NF－kB活性和TNF－α含量在刺激后0.5-4h明显高于正常对照组;IL－10＋LPS组NF-kB活性和TNF-α含量均显著低于LPS组。结论 LBS诱导PAM的NF－kB活化,导致TNF－α基因表达增强;白介素－10可抑制NF－kB活化而减少TNF－α的释放。     

Muramyl dipeptide activation of nucleotide-binding oligomerization domain 2 protects mice from experimental colitis

The mechanisms underlying the susceptibility of individuals with caspase recruitment domain 15 (CARD15) mutations and corresponding abnormalities of nucleotide-binding oligomerization domain 2 (NOD2) protein to Crohn disease are still poorly understood. One possibility is based on previous studies showing that muramyl dipeptide (MDP) activation of NOD2 negatively regulates TLR2 responses and that absence of such regulation leads to heightened Th1 responses. We now report that administration of MDP protects mice from the development of experimental colitis by downregulating multiple TLR responses, not just TLR2. The basis of these in vivo findings was suggested by in vitro studies of DCs, in which we showed that prestimulation of cells with MDP reduces cytokine responses to multiple TLR ligands and this reduction is dependent on enhanced IFN regulatory factor 4 (IRF4) activity. Further studies of mouse models of colitis showed that this inhibitory role of IRF4 does in fact apply to MDP-mediated protection from colitis, since neither IRF4-deficient mice nor mice treated with siRNA specific for IRF4 were protected. These findings indicate that MDP activation of NOD2 regulates innate responses to intestinal microflora by downregulating multiple TLR responses and suggest that the absence of such regulation leads to increased susceptibility to Crohn disease.     

IKappaB-kinase/nuclear factor-kappaB signaling prevents thermal injury-induced gut damage by inhibiting c-Jun NH2-terminal kinase activation

OBJECTIVE: The molecular mechanism of major burn-induced gut damage is not clear. This study is to determine whether IkappaB-kinase (IKK)/nuclear factor-kappaB signaling in intestinal mucosa maintains gut function through the regulation of the c-Jun NH2-terminal kinase (JNK) and p38 phosphorylation. DESIGN: Prospective, experimental study. SETTING: Research laboratory at a university hospital. SUBJECTS: Thermal injury models in mice. INTERVENTIONS: Conditional intestinal epithelial cell IKKbeta knockout (Vil-Cre/Ikkbeta(F/Delta) mice and control (Ikkbeta(F/Delta) mice were subjected to 30% total body surface area third-degree burn. JNK inhibitor (SP600125) or p38 inhibitor (SB203580) was given to mice immediately after burn injury. MEASUREMENTS AND MAIN RESULTS: Thermal injury induced a significant increase of intestinal permeability, nuclear factor-kappaB DNA-binding activity, phosphorylated JNK, phosphorylated p38, and caspase 3 expression of intestinal mucosa in Vil-Cre/Ikkbeta(F/Delta) mice compared with those of Ikkbeta(F/Delta) mice. BCL-xL and cellular FLICE inhibitory protein, but not GADD45beta (growth arrest and DNA damage-inducing protein beta), cellular inhibitor of apoptosis 1, Bfl-1, or TRAIL, messenger RNA expression was significantly decreased in Vil-Cre/Ikkbeta(F/Delta) mice compared with that of Ikkbeta(F/Delta) mice. SP600125 decreased intestinal permeability and increased phosphorylated p38 and tumor necrosis factor receptor-associated factor 2 expression of intestinal mucosa in Vil-Cre/Ikkbeta(F/Delta) mice. SB203580 treatment enhanced thermal injury-induced gut damage in Vil-Cre/Ikkbeta(F/Delta) mice. CONCLUSIONS: Thermal injury induces nuclear factor-kappaB activation of intestinal mucosa and IKK protects intestinal mucosa from thermal injury-induced gut damage. IKK blocks caspase 3 expression by up-regulating BCL-xL and cellular FLICE inhibitory protein expression. IKK inhibits JNK and p38 but not p44/42 phosphorylation of intestinal mucosa. JNK inhibition increases p38 and tumor necrosis factor receptor-associated factor 2 expression and decreases thermal injury-induced gut damage. Taken together with the enhanced thermal injury-induced gut damage by p38 inhibition, we conclude that IKK maintains gut function by inhibiting JNK phosphorylation, which suppresses p38 phosphorylation and induces gut damage.     

Anti-CD146 monoclonal antibody AA98 inhibits angiogenesis via suppression of nuclear factor-kappaB activation

Our previous study showed that an anti-CD146 monoclonal antibody (mAb), AA98, which was raised against the vascular endothelial cells stimulated by a conditioned medium from hepatocarcinoma SMMC 7721 cells (SMMC 7721-CM), inhibited cell migration, angiogenesis, and tumor growth. However, the underlying mechanism was not elucidated. The objective of this study was to understand the mechanism by which mAb AA98 inhibits the endothelial cell migration and angiogenesis that is induced by SMMC 7721-CM. Using confocal imaging and biochemical studies, we found that SMMC 7721-CM induced nuclear factor kappaB (NF-kappaB) activation through the upstream p38 mitogen-activated protein kinase pathway, leading to the up-regulation of matrix metalloproteinase 9 and intercellular adhesion molecule 1 expression. Interestingly, all these activities stimulated by SMMC 7721-CM could be effectively inhibited by mAb AA98 in a dose- and time-dependent manner. Our data showed that the engagement of mAb AA98 with membrane protein CD146 inhibited p38 mitogen-activated protein kinase phosphorylation, suppressed NF-kappaB activation, and down-regulated matrix metalloproteinase 9 and intercellular adhesion molecule 1 expression, suggesting that the suppression of NF-kappaB is a critical point for the inhibitory function of mAb AA98 on endothelial cell migration, angiogenesis, and tumor metastasis. These results will provide clues for a better understanding of the mechanisms underlying tumor angiogenesis as well as antiangiogenesis therapy.     

YC-1 suppresses constitutive nuclear factor-kappaB activation and induces apoptosis in human prostate cancer cells

Although the indazole compound, YC-1, is reported to exert anticancer activities in several cancer cell types, its target and mechanism of action have not been well explored. The objectives of this study were to ascertain whether YC-1 directly induces apoptosis in prostate cancer cells and to explore the mechanism(s) whereby YC-1 causes cell death. Hormone-refractory metastatic human prostate cancer PC-3 cells were selected for this study. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay indicated that YC-1 suppresses growth of PC-3 cells in a concentration-dependent and time-dependent manner. Apoptosis was determined using 4',6-diamidino-2-phenylindole staining, and cell cycle progression was examined by FACScan flow cytometry. YC-1 treatment showed chromatin condensation and increased the percentage of PC-3 cells in the hypodiploid sub-G0-G1 phase, indicative of apoptosis. Additionally, exposure to YC-1 was found to induce activation of caspase-3 and cleavage of poly(ADP-ribose) polymerase. Translocation and activation of nuclear factor-kappaB (NF-kappaB) were determined by immunofluorescent staining and ELISA, respectively. The results showed that YC-1 abolished constitutive nuclear translocation and activation of NF-kappaB/p65. Furthermore, inhibition of inhibitor of kappaBalpha (IkappaBalpha) phosphorylation and accumulation of IkappaBalpha were observed. The antitumor effects of YC-1 were evaluated by measuring the growth of tumor xenografts in YC-1-treated severe combined immunodeficient mice. The volumes of PC-3 tumors produced in severe combined immunodeficient mice were observed to decline significantly after treatment with YC-1 compared with vehicle controls. We concluded that the antitumor effects of YC-1 in PC-3 cells include the induction of apoptosis and the suppression of NF-kappaB activation. Given these unique actions, further investigations of the effects of YC-1 against hormone-refractory prostate cancer are warranted.