T cell-derived Act1 is necessary for IL-25-mediated Th2 responses and allergic airway inflammation

The cellular and molecular mechanisms driven by IL-25 and its cognate receptor IL-17RB necessary for the promotion of Th2-mediating pathogenic pulmonary inflammation remains to be defined. We have previously reported the critical role of the U-box-type E3 ubiquitin ligase Act1 (1) for the downstream signaling of the IL-17 cytokine family including the Th2-promoting cytokine IL-25 (IL-17E) (2). In this study, we report that IL-25-driven but not conventional IL-4-driven Th2 polarization and cytokine production is impaired in Act1-deficient T cells. Also, Act1 deficiency in the T cell compartment results in the abrogation of eosinophilic airway infiltration as well as airway hyperresponsiveness in mouse models of Ag-induced airway inflammation. The in vivo generation of Ag-specific Th2 cytokine-producing cells is defective in the absence of Act1 expression in T cells after OVA/aluminum hydroxide immunization. Notably, the production of OVA-specific IgG(1) but not IgG(2a) or IgE is also impaired. At the molecular level, we report that IL-25-mediated induction of Th2 master regulator GATA-3 and the transcription factor GFI-1 is attenuated in Act1-deficient T cells. Taken together, our findings indicate that Act1 expression in T cells is required for cellular and humoral Th2-mediated allergic responses and the development of airway hyperresponsiveness, in part, through Act1's function in IL-25-induced development of Th2 T cells.

The kinase activity of interleukin-1 receptor-associated kinase 2 is essential for lipopolysaccharide-mediated cytokine and chemokine mRNA stability and translation

Interleukin-1 receptor-associated kinase 2 (IRAK2) has been shown to be essential for lipopolysaccharide (LPS)-mediated posttranscriptional control of cytokine and chemokine production. In this study, we investigated the role of IRAK2 kinase activity in LPS-mediated posttranscriptional control by reconstituting IRAK2-deficient macrophages with either wild-type or kinase-inactive IRAK2. Compared with wild-type IRAK2 (IRAK2-WT) macrophages, kinase-inactive IRAK2 (IRAK2-KD) macrophages show reduced cytokine and chemokine mRNA stability and translation in response to LPS. Further, LPS-treated IRAK2-KD macrophages also show reduced activation of MKK3/6, MNK1, and eIF4E and attenuated toll-like receptor 4-induced tristetraprolin modification and stabilization. Taken together, these results suggest that the kinase activity of IRAK2 is required for the optimal activation of mitogen-activated protein kinase signaling, which regulates cytokine and chemokine production at posttranscriptional levels.

The dual functions of IL-1 receptor-associated kinase 2 in TLR9-mediated IFN and proinflammatory cytokine production

Bone marrow-derived plasmacytoid dendritic cells (pDCs) from IL-1R-associated kinase (IRAK)2-deficient mice produced more IFNs than did wild-type pDCs upon stimulation with the TLR9 ligand CpG. Furthermore, in CpG-stimulated IRAK2-deficient pDCs there was increased nuclear translocation of IFN regulatory factor 7, the key transcription factor for IFN gene transcription in these cells. In IRAK2-deficient macrophages, enhanced NF-κB activation and increased expression of CpG-induced genes were detected within 2 h after treatment. However, at later times, NF-κB activation was decreased and, in contrast to the results with IFN, there was less secretion of other proinflammatory cytokines (such as TNF-α) and chemokines in CpG-stimulated IRAK2-deficient pDCs and macrophages. Therefore, although IRAK2 is a negative regulator of TLR9-mediated IFN production through its modulation of the transcriptional activity of IFN regulatory factor 7, it is also a positive regulator of TLR9-mediated proinflammatory cytokine and chemokine production at some level subsequent to transcription.

Properties of hepatitis C virus minigenome containing mutated 5'UTR region and luciferase transgene

Sequences at the 3'UTR of Hepatitis C virus (HCV) negative-strand (-)RNA play an important role in the initiation of positive-strand (+)RNA synthesis. However, the underlying mechanism in cellular context is still unclear. In this report, we designed several cDNA-based HCV-like minigenomes containing different mutations at the 5'UTR of (+)RNA. These (+)RNAs transcribed from the minigenomes in vitro were transfected into HCV replicon cells for producing (-)RNAs with deletions of different stem loops (SL) at the 3'-end. The results showed that expression of the antisense transgene from minigenome increased, when the minigenome containing deletion of SL-C1+D1+E1 at the 3'-end of (-)RNA was transfected into the HCV replicon cells compared to that of the full minigenome. The expression of the transgene from minigenome decreased using other mutant minigenomes containing deletions SL-A1, SL-A1+B1, and SL-A1+B1+C1 at the 3'-end of (-)RNA. Finally, the transgene from SL-C1+D1+E1 of (-)RNA using CMV promoter-driven minigenome was expressed at higher level than full minigenome in HCV replicon cell lines. These results indicated that the region of (-)RNA interacting with HCV replicase may locate in the SL-C1+D1+E1 region of (-)RNA.

KEYWORDS

Hepatitis C virus; minigenome; RNA dependent RNA polymerase; replication.

Loss of single immunoglobulin interlukin-1 receptor-related molecule leads to enhanced colonic polyposis in Apc(min) mice

BACKGROUND & AIMS

Commensal bacteria can activate signaling by the Toll-like and interleukin-1 receptors (TLR and IL-1R) to mediate pathogenesis of inflammatory bowel diseases and colitis-associated cancer. We investigated the role of the single immunoglobulin IL-1 receptor-related (SIGIRR) molecule, a negative regulator of TLR and IL-1R signaling, as a tumor suppressor to determine whether SIGIRR controls cell-cycle progression, genetic instability, and colon tumor initiation by modulating commensal TLR signaling in the gastrointestinal tract.

METHODS

We analyzed adenomatous polyposis coli (Apc)min/+/Sigirr-/- mice for polyps, microadenomas, and anaphase bridge index. Commensal bacteria were depleted from mice with antibiotics. Akt, mammalian target of rapamycin (mTOR), and beta-catenin pathways were examined by immunoblotting and immunohistochemistry. Loss of heterozygosity of Apc and expression of cytokines and proinflammatory mediators were measured by nonquantitative or quantitative polymerase chain reaction.

RESULTS

Apcmin/+/Sigirr-/- mice had increased loss of heterozygosity of Apc and microadenoma formation, resulting in spontaneous colonic polyposis, compared with Apcmin/+/Sigirr+/+ mice. The increased colonic tumorigenesis that occurred in the Apcmin/+/Sigirr-/- mice depended on the presence of commensal bacteria in the gastrointestinal tract. Cell proliferation and chromosomal instability increased in colon crypt cells of the Apcmin/+/Sigirr-/- mice. Akt, mTOR, and their substrates were hyperactivated in colon epithelium of Apcmin/+/Sigirr-/- mice in response to TLR or IL-1R ligands. Inhibition of the mTOR pathway by rapamycin reduced formation of microadenomas and polyps in the Apcmin/+/Sigirr-/- mice.

CONCLUSIONS

SIGIRR acts as a tumor suppressor in the colon by inhibiting TLR-induced, mTOR-mediated cell-cycle progression and genetic instability.

TP63 gene mutations in Chinese P63 syndrome patients

TP63 plays an essential role in the development of epidermis and skin appendages. Mutations in TP63 can give rise to a series of syndromes characterized by various combinations of ectodermal dysplasia, limb malformations, and orofacial clefting in many populations. To test whether TP63 is the disease-causative gene for these phenotypes in Chinese, we recruited two Chinese Ectrodactyly-Ectodermal-dysplasia-Cleft lip/palate syndrome (EEC) cases and a Limb-Mammary-Syndrome (LMS) patient to carry out TP63 gene sequencing. Three missense mutation, c.812G>C (Ser271Thr), c.611G>A (Arg204Gln), and c.680G>A (Arg227Gln), which lead to the substitution of highly conserved amino acids in the DNA-binding domain of TP63, were identified. These mutations were predicted to disrupt DNA-binding specificity and affinity. To our knowledge, this is the first report of EEC and LMS syndromes in individuals of Chinese descent. Analysis of our data demonstrated that TP63 is critical for the development of ectoderm in humans.

Intermittent Hypoxia: Potential Factor of Resistance to Endocrine Therapy

Background: It has been reported that intermittent hypoxia, which is likely more prevalent than acute hypoxia in breast cancers, can cause persistent depression of estrogen receptor alpha (ER-α) expression in breast cell lines. However, it remains suspension whether intermittent hypoxia may be associated with resistance to endocrine therapy.Material and methods: The role of intermittent hypoxia in resistance to endocrine therapy was investigated in ER-α positive breast cell lines and animal models.Results: We observed that intermittent hypoxia promoted cancer cell proliferation in vitro and in vivo compared with normoxia. At both mRNA and protein levels, intermittent hypoxia induced down-regulation of ER-α and factor inhibiting HIF-1 (FIH) as well as up-regulation of hypoxia inducible factor-1 alpha (HIF-1α) and carbonic anhydrase IX (CA-IX). ER-α positive breast cancer cells under normoxic condition were capable of an intact response to ICI 182,780 (Tocris), whereas the inhibitory effect of ICI 182,780 (Tocris) was significantly reduced in those after intermittent hypoxia. Such effect was further validated with fulvestrant (Astrazeneca) in the animal models. To clarify whether intermittent hypoxia was associated with resistance to endocrine therapy, the expression of HIF-1α, a critical regulator of hypoxia-related pathway, was blocked by a reformed type of small interfering RNA (siRNA), stealth RNAi (Invitrogen), which can reduce the cytotoxic interferon response unlike conventional siRNA. Interestingly, knock-down of HIF-1α did result in the restoration of not only the ER-α expression but also the response to endocrine therapy, which was reproducible with administration of Bortezomib, a proteasome inhibitor of HIF-1α.Discussion: These data provide functional evidence that intermittent hypoxia may confer resistance to endocrine therapy in breast cancers through the crosstalk between HIF-1α and ER-α signaling, which holds a promise to overcome endocrine resistance.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5148.

Epidemiology of Triple Negative Breast Cancer in China

Background:The classification of tumors based on the gene expression may define intrinsic breast cancer subtypes in which the effect of risk factors could be more obvious. We sought to assess the risk factors for triple negative breast cancer on Chinese population.Methods: A retrospective study of 5761 patients was carried out from a large database of breast cancer patients undergoing surgery between January 1, 1991 and June 31, 2008 in Cancer Hospital, Fudan University, Shanghai, China. Univariate analyses were performed by chi-square test of Student's t test and multivariate analyses by logistic regression.Results: A total of 1108 women were identified as having triple negative breast cancer and were compared with the 4653 women with non-triple negative. Regardless the pathological discrepancy, women with triple negative breast cancers were significantly more likely to be younger age(P=0.001; OR=1.615, 95%CI=1.207-2.160), premenopausal (P = 0.003; OR = 1.570, 95% CI = 1.171-2.106) and parous women (P = 0.001; OR = 1.741, 95% CI = 1.269-2.387).There seems no associations with increasing risk of triple negative breast cancer for breastfeeding (P=0.126), younger age at menarche (P=0.129), first degree family history (P=0.111) and oral contraceptive usage (P=0.251).Conclusion:Based on this large population study in Chinese breast cancer patients, the risk factors for triple negative phenotype may be somewhat different from those for Western women. Therefore, a better knowledge of this issue is warranted due to it may have impact on clinical outcomes and may offer some insight into the process of carcinogenesis and therapeutic efficacy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2065.

Serum complement activation on heterologous platelets is associated with arterial thrombosis in patients with systemic lupus erythematosus and antiphospholipid antibodies

Complement plays a major role in inflammation and thrombosis associated with systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS). A cross-sectional retrospective analysis was performed to evaluate serum complement fixation on platelets and thrombotic incidence using banked sera and clinical data from patients with SLE (n = 91), SLE with antiphospholipid antibodies (aPL) or APS (n = 78) and primary aPL (n = 57) or APS (n = 96). In-situ complement fixation was measured as C1q and C4d deposition on heterologous platelets using an enzyme-linked immunosorbent assay approach. Platelet activation by patient serum in the fluid phase was assessed via serotonin release assay. Enhanced in-situ complement fixation was associated with the presence of IgG aPL and IgG anti-beta2 glycoprotein 1 antibodies (P < 0.05) and increased platelet activation (P < 0.005). Moreover, enhanced complement fixation, especially C4d deposition on heterologous platelets, was positively associated with arterial thrombotic events in patients with SLE and aPL (P = 0.039). Sera from patients with aPL possess an enhanced capacity for in-situ complement fixation on platelets. This capacity may influence arterial thrombosis risk in patients with SLE.

Activity and radiation protection studies for the W-Ta target of CSNS

The Chinese government initiated a conceptual design for the project of China Spallation Neutron Source (CSNS), which consists of an H-linear accelerator, a rapid cycling synchrotron accelerating the beam to 1.6 GeV, a target station converting proton beam into lower energy (<1 eV) neutron beam optimised to instruments for neutron scattering applications. The facility operates at 25-Hz repetition rate with an initial beam power of 100 kW. In the target station, the target-moderator-reflector (TMR) components are exposed to the intensive fluxes of high-energy hadrons and become highly radioactive as a result of long-time irradiation. In this paper, the activity of the TMR components are calculated using the Monte Carlo code system LAHET&MCNP4C&CINDER'90. Comparisons of some results with that simulated by FLUKA code are also performed. Detailed analyses of the radionuclides and their characters in the tantalum clad tungsten target (W-Ta target) are important for the radiation protection of the CSNS target station. The shielding design of the service cell for the decay gamma ray induced from the W-Ta target and its vessel shows that the ambient dose rate decreases exponentially with increasing heavy concrete thickness. And 80 cm thickness of heavy concrete for each side of the service cell can satisfy the safety requirement.

Phylogeographical analysis of an estuarine fish, Salanx ariakensis (Osmeridae: Salanginae) in the north-western Pacific

This study extended the geographic coverage of a previous study to explore population genetic structure and demographic history in the Ariake icefish Salanx ariakensis from three populations of continental coastlines and one island population in the north-western Pacific based on a partial sequence of the mitochondrial cytochrome b gene. The S. ariakensis showed high genetic diversity and strong genetic structure. Phylogenetic analysis showed a shallow gene tree with no clear phylogeographical structure. Contiguous range expansion and restricted gene flow were inferred to be main population events by nested-clade analysis. Significant genetic differentiations between populations could be attributable to negligible gene flow by coalescent analysis. High nucleotide diversity of each population was due to geographic mixing of heterogenous haplotypes during lowering sea levels of the Pleistocene. These findings indicate that cycles of geographic isolation and secondary contact happened in the Pleistocene glacial-interglacial cycles shaping genetic structure and population demography of S. ariakensis.

Linear growth patterns in prepubertal children following liver transplantation

Factors impacting linear growth following pediatric liver transplantation (LT) are not well understood. This longitudinal analysis examines predictors of linear growth impairment in prepubertal children included in Studies of Pediatric Liver Transplantation. In 1143 children with serial measurements, mean height scores increased from -1.55 at LT to -0.87 and -0.68 at 24 and 36 months post LT with minimal subsequent catch up growth observed until 60 months. Subgroup analysis of height measurements at 24 months (n = 696), 33.8% were below 10th percentile at 24 months post LT. Multivariate analysis revealed linear growth impairment more likely in patients with metabolic disease (OR 4.4, CI: 1.83-10.59) and >18 months of steroids exposure (OR 3.02, CI: 1.39-6.55). Higher percentiles for weight (OR 0.80, CI: 0.65-0.99) and height (OR 0.62, CI: 0.51-0.77) at LT decreased risk. Less linear catch up was observed in patients with metabolic disease, non-Biliary atresia cholestatic diseases and lower weight and higher height percentiles prior to LT. Prolonged steroid exposure and elevated calculated glomerular filtration rate and gamma-Glutamyltransferase following LT were associated with less catch up growth. Linear growth impairment and incomplete linear catch up growth are common following LT and may improve by avoiding advanced growth failure before LT and steroid exposure minimization.

Postsurgical drainage and the risk of breast cancer recurrence in Chinese breast cancer patients

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Background: Clinical investigations suggest that while primary breast cancer surgical removal favorably modifiers the natural history of breast cancer. Postoperative drainage, a surgery-derived discharge after breast cancer surgery, reflecting some biological features of surgical stimulation, was assessed and explored its relationship with breast cancer recurrence in this study. Methods: A total of 1445 women undergoing surgery between Jan 1, 2000 and Dec31, 2002 in Cancer Hospital of Fudan University, Shanghai, China was retrospectively studied. Survival curves were performed with Kaplan-Meier method and the predictive value of postsurgical drainage was estimated using proportional Cox regression model. Conclusions: The larger drainage volume POD 1 is a useful marker, suggesting a greater stimulation to surgical treatment compared to the lower ones. Awareness of the relationship between early surgery-stimulated effects and harmful wound healing response might help to explore new strategies to block or deplete these harmful effects, resulting in improving patients' survival.

No significant financial relationships to disclose.

Demographic features and prognostic profiles of breast cancer patients presenting with nipple discharge in Chinese population

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Background: Breast cancer patients with nipple discharge (ND) may constitute a distinct clinical entity compared to those without ND, which has not been well elucidated in previous reports. We sought to analyze the demographic features and prognostic profiles of breast cancer patients presenting with nipple discharge in Chinese population. Methods: A total of 3234 patients, categorized as ND (2.47%) and non-nipple discharge (NND; 97.53%) according to different initial signs, were retrospectively analyzed. Survival curves were performed with Kaplan-Meier method and annual recurrence hazard was estimated by hazard function. Results: ND group tended to have smaller tumors and less axillary lymph node (ALN) involvement than NND group (P < 0.05). In the univariate analysis, we found significantly different recurrence-free survivals (RFS) between subgroups (P = 0.0182), with the rate of 77.78% for ND group and 72.46% for the other at the 11th year respectively. In Cox proportional hazards regression analysis, we found that tumor size (P < 0.001), ALN status (P < 0.001) were independent prognostic factors for RFS. To further evaluate whether prognostic effect of ND status remained unabated over time, the test for lack of proportionality was performed. However, it was statistically significant (global test, P = 0.039), which hinted at a demand for the employment of Cox non-proportional hazards regression in this analysis. In time dependent Cox model, ND status (P = 0.0495) as well as ERBB2 status (P = 0.017), tumor size (P < 0.001), ALN status (P < 0.001) were independent prognostic factors when ND and ERBB2 status were taken as time-varying covariates. Annual hazard rates for recurrence remained lower on ND group until approximately 4.5 years after surgery, while the situation was just the opposite thereafter. Conclusions: Our findings suggested that demographic features and prognostic profiles were quite different between breast cancers presenting with and without ND in Chinese population, which may indirectly uncover distinct biological behaviors and potentially enlighten novel therapeutic approaches for patients with different initial signs.

No significant financial relationships to disclose.

The critical role of epithelial-derived Act1 in IL-17- and IL-25-mediated pulmonary inflammation

IL-25 initiates, promotes, and augments Th2 immune responses. In this study, we report that Act1, a key component in IL-17-mediated signaling, is an essential signaling molecule for IL-25 signaling. Although Act1-deficient mice showed reduced expression of KC (CXCL1) and neutrophil recruitment to the airway compared with wild-type mice in response to IL-17 stimulation, Act1 deficiency abolished IL-25-induced expression of IL-4, IL-5, IL-13, eotaxin-1 (CCL11), and pulmonary eosinophilia. Using a mouse model of allergic pulmonary inflammation, we observed diminished Th2 responses and lung inflammation in Act1-deficient mice compared with wild-type mice. Importantly, Act1 deficiency in epithelial cells reduced the phenotype of allergic pulmonary inflammation due to loss of IL-17-induced neutrophilia and IL-25-induced eosinophilia, respectively. These results demonstrate the essential role of epithelial-derived Act1 in allergic pulmonary inflammation through the distinct impact of the IL-17R-Act1 and IL-25R-Act1 axes. Such findings are crucial for the understanding of pathobiology of atopic diseases, including allergic asthma, which identifies Act1 as a potential therapeutic target.