Global spread and genetic variants of the two CYP9M10 haplotype forms associated with insecticide resistance in Culex quinquefasciatus Say

Insecticide resistance develops as a genetic factor (allele) conferring lower susceptibility to insecticides proliferates within a target insect population under strong positive selection. Intriguingly, a resistance allele pre-existing in a population often bears a series of further adaptive allelic variants through new mutations. This phenomenon occasionally results in replacement of the predominating resistance allele by fitter new derivatives, and consequently, development of greater resistance at the population level. The overexpression of the cytochrome P450 gene CYP9M10 is associated with pyrethroid resistance in the southern house mosquito Culex quinquefasciatus. Previously, we have found two genealogically related overexpressing CYP9M10 haplotypes, which differ in gene copy number (duplicated and non-duplicated). The duplicated haplotype was derived from the non-duplicated overproducer probably recently. In the present study, we investigated allelic series of CYP9M10 involved in three C. quinquefasciatus laboratory colonies recently collected from three different localities. Duplicated and non-duplicated overproducing haplotypes coexisted in African and Asian colonies indicating a global distribution of both haplotype lineages. The duplicated haplotypes both in the Asian and African colonies were associated with higher expression levels and stronger resistance than non-duplicated overproducing haplotypes. There were slight variation in expression level among the non-duplicated overproducing haplotypes. The nucleotide sequences in coding and upstream regions among members of this group also showed a little diversity. Non-duplicated overproducing haplotypes with relatively higher expression were genealogically closer to the duplicated haplotypes than the other non-duplicated overproducing haplotypes, suggesting multiple cis-acting mutations before duplication.

Retention of tocilizumab and anti-tumour necrosis factor drugs in the treatment of rheumatoid arthritis

OBJECTIVES

The retention of the anti-rheumatic agent tocilizumab (TCZ) has not been well documented in patients with rheumatoid arthritis (RA). We conducted an observational study to compare the retention of TCZ and anti-tumour necrosis factor (TNF) drugs in the treatment of patients with RA.

METHOD

We reviewed continuation rates and causes of discontinuation of biological agents (biologics) by assessing medical records of patients with RA who were administered biologics at our institute from September 1999 to April 2012, using the Osaka University Biologics for Rheumatic Diseases (BiRD) registry.

RESULTS

A total of 401 patients were included. TCZ, infliximab (IFX), etanercept (ETN), and adalimumab (ADA) were administered to 97, 103, 143, and 58 patients, respectively. There were some differences between the baseline characteristics of the groups. The median duration (range) of TCZ, IFX, ETN, and ADA administration was 2.5 (0.1-12.6), 1.9 (0.0-7.7), 2.9 (0.0-11.3), and 1.3 (0.0-3.4) years, respectively. Continuation rates for TCZ and ETN were significantly higher than those for IFX and ADA. Multivariate analyses showed that discontinuation due to lack or loss of efficacy was significantly less common in the TCZ group than in the other groups. Discontinuation due to overall adverse events was not significantly different between treatment groups.

CONCLUSION

TCZ and ETN show better retention than IFX or ADA in the treatment of RA.

REG Iα is a biomarker for predicting response to chemotherapy with S-1 plus cisplatin in patients with unresectable stage IV gastric cancer

Background:

The regenerating gene Iα (REG Iα) is involved in gastric carcinogenesis as an antiapoptotic factor. Therefore, we investigated whether REG Iα confers resistance to chemotherapeutic drugs in gastric cancer (GC) cells and whether REG Iα expression is useful for predicting the response to chemotherapy and outcome in patients with GC.

Methods:

A total of 70 patients with unresectable stage IV GC received first-line chemotherapy with S-1 and cisplatin (S-1/CDDP). The expression of REG Iα was evaluated immunohistochemically using biopsy samples obtained before chemotherapy, and its relationship to clinicopathological parameters was analysed statistically. The effects of REG Iα gene induction on resistance to 5-FU or CDDP treatment were examined by cell survival assay and flow cytometry.

Results:

Of the 70 patients with unresectable stage IV GC, 19 (27%) were positive for REG Iα expression. The expression of REG Iα was independently predictive of poorer progression-free and overall survival in such patients (hazard ratio (HR) 2.46; P=0.002 and HR 1.89; P=0.037, respectively). The gene induction of REG Iα conferred resistance to cell death induced by 5-FU or CDDP in GC cells.

Conclusion:

In patients with stage IV GC, REG Iα, which confers resistance to chemotherapeutic drugs in GC cells, is a potential biomarker for predicting resistance to S-1/CDDP treatment.

Juvenile pilocytic astrocytoma in association with arteriovenous malformation

Pilocytic astrocytomas are highly vascular, relatively common primary brain tumors in the pediatric population, but their association with a true arteriovenous malformation (AVM) is extremely rare. We describe an eight-year-old girl with a right supratentorial juvenile pilocytic astrocytoma (WHO grade I) with an angiographically documented AVM entangled in the tumor mass who presented with intracranial hemorrhage due to a ruptured anterior choroidal artery pseudoaneurysm encased in the lesion. The AVM nidus as well as the hemorrhage site was embolized with Onyx. A literature review revealed only one previous report of a true intermixture of these two lesions. We hypothesize whether the association of vascular malformations and primary brain tumors are merely coincidental or if they point to the existence of a distinct entity and/or a common etiologic factor.

Generation of dyspeptic symptoms by direct acid and water infusion into the stomachs of functional dyspepsia patients and healthy subjects

BACKGROUND

The mechanisms of the development of symptoms in functional dyspepsia (FD) patients have not been fully elucidated. We previously reported that acid directly infused into the stomach causes dyspeptic symptoms in asymptomatic healthy controls (HCs); however, the response to acid infusion of FD patients was not determined.

AIM

To investigate the severity of dyspeptic symptoms induced by direct acid infusion in FD subjects and HCs.

METHODS

This was a multi-centre, cross-over, randomised, double-blind study in 23 FD subjects and 32 HCs. FD was defined using the Rome III criteria. All subjects were Helicobacter pylori negative. Each subject received two tests; 0.1 mol/L hydrochloric acid and water infused into the stomach. The presence and severity of 12 dyspeptic symptoms were assessed using a visual analogue scale.

RESULTS

The proportion of subjects developing symptoms by acid or water infusion was significantly greater in FD subjects than HCs. All of the FD subjects experienced at least one symptom by water or acid infusion. In the FD subjects, the severity of symptoms was significantly greater with acid infusion than water infusion. The severity of symptoms in total and the scores for eight of the 12 symptoms induced by acid infusion was significantly greater in FD subjects than in HCs.

CONCLUSIONS

The severity of dyspeptic symptom generation induced by direct acid infusion into the stomach was significantly greater in functional dyspepsia subjects than in healthy controls, suggesting that hypersensitivity to acid is one of the important mechanisms of the development of symptoms in functional dyspepsia patients.

Azilsartan treatment improves insulin sensitivity in obese spontaneously hypertensive Koletsky rats

AIM

Hypertension often coexists with insulin resistance. However, most metabolic effects of the antihypertensive agents have been investigated in nomotensive animals, in which different conclusions may arise. We investigated the metabolic effects of the new angiotensin II type 1 receptor blocker azilsartan using the obese Koletsky rats superimposed on the background of the spontaneously hypertensive rats.

METHODS

Male Koletsky rats were treated with azilsartan (2 mg/kg/day) over 3 weeks. Blood pressure was measured by tail-cuff. Blood biochemical and hormonal parameters were determined by enzymatic or ELISA methods. Gene expression was assessed by RT-PCR.

RESULTS

In Koletsky rats, azilsartan treatment lowered blood pressure, basal plasma insulin concentration and the homeostasis model assessment of insulin resistance index, and inhibited over-increase of plasma glucose and insulin concentrations during oral glucose tolerance test. These effects were accompanied by decreases in both food intake and body weight (BW) increase. Although two treatments showed the same effect on BW gain, insulin sensitivity was higher after azilsartan treatment than pair-feeding. Azilsartan neither affected plasma concentrations of triglyceride and free fatty acids, nor increased adipose mRNA levels of peroxisome proliferator-activated receptor (PPAR)γ and its target genes such as adiponectin, aP2. In addition, azilsartan downregulated 11β-hydroxysteroid dehydrogenase type 1 expression.

CONCLUSIONS

These results show the insulin-sensitizing effect of azilsartan in obese Koletsky rats. This effect is independent of decreases in food intake and BW increase or of the activation of adipose PPARγ. Our findings indicate the possible usefulness of azilsartan in the treatment of metabolic syndrome.

Estrogen-dependent activation of neutral cholesterol ester hydrolase underlying gender difference of atherogenesis in apoE-/- mice

OBJECTIVE

Mechanisms underlying gender difference of atherogenesis were investigated focusing on direct effects of estrogen on the artery.

METHODS

First, male and female apoE(-/-) mice were fed an atherogenic diet for 16 weeks from 10 weeks of age. Second, female apoE(-/-) mice were ovariectomized (ovx) or sham operated at 8 weeks of age, and 2-weeks afterwards, one-third of each ovx-group received conjugated equine estrogens (CEE) (0, 2.5 or 5.0 μg/day) for 16 weeks. Atherosclerotic lesions were examined after experimental periods. To clarify anti-atherogenic effect of 17β-estradiol (E2) on artery, neutral cholesteryl ester hydrolase (N-CEase) activity in aorta and peritoneal macrophages, and E2-treated J774A.1 cells were measured.

RESULTS

First, atherosclerotic lesion in female mice was significantly less than male mice without any changes in serum lipids and lipoprotein profile. N-CEase activity in aorta and peritoneal macrophages in female mice was significantly higher than male mice. Second, atherosclerotic lesion in ovx-group was significantly greater than sham-group. CEE-replacement to ovx-group decreased atherosclerotic lesion in a dose-dependent manner. N-CEase activity in aorta and peritoneal macrophages was decreased in ovx-group compared to sham-group, and restored by CEE-replacement in macrophages. To study detailed mechanisms, J774A.1 cells were treated with E2. E2 significantly increased N-CEase activity, and cAMP-dependent protein kinase (A-kinase) type II activity and the protein in cytosol fraction without any changes of total protein of A-kinase type II.

CONCLUSION

These results suggest that gender difference of atherogenesis is partly accounted for activation of N-CEase through estrogen-dependent translocation of A-kinase type II in macrophages.

Imbalance of Clara cell-mediated homeostatic inflammation is involved in lung metastasis

We have previously shown that tumor necrosis factor (TNF)α produced from primary tumor-induced expression of two endogenous Toll-like receptor 4 (TLR4) ligands, S100A8 and serum amyloid A3 (SAA3), in pre-metastatic lungs. However, mechanistic details of the signaling network and relevance to pulmonary physiology are poorly understood. Here, we identify Clara cells as a control tower of the network. Clara cell ablation by naphthalene suppressed pulmonary recruitment of CD11b+TLR4+ cells and spontaneous lung metastasis. Clara cells turned out to express TLR4 through which SAA3 was auto-amplified. Reciprocal bone marrow transplantation between wild-type and TLR4 knockout mice demonstrated that pulmonary TLR4+ Clara cells could be derived from bone marrow. SAA3-induced TNFα expression in both alveolar type II cells and macrophages. Primary co-cultures of alveolar type II cells and Clara cells revealed that the induction of TNFα in alveolar type II cells was dependent on the Clara cell-mediated amplification of SAA3. SAA3 induction by bacterial endotoxin also required both Clara cells and TLR4. Thus, pulmonary metastatic soil may feature deregulation of homeostatic inflammatory responses to constant assaults of microbes with endotoxin.

Use of isogenic strains indicates CYP9M10 is linked to permethrin resistance in Culex pipiens quinquefasciatus

Previous studies on a strain of Culex pipiens quinquefasciatus from Saudi Arabia indicated permethrin resistance was a result of cytochrome P450 mediated detoxification and kdr. The P450 detoxification was found to be larval specific and associated with a fitness cost in certain environments. The P450 responsible for resistance (and the fitness cost) has not been identified, but recently two candidate P450s (CYP4H34 and CYP9M10) have been found. We measured cytochrome P450 and cytochrome b₅ content as well as the expression levels of CYP4H34 and CYP9M10 in a susceptible (SLAB) and two isogenic strains (isolated by repeated backcrossing and selection) of mosquito (ISOP450 and ISOJPAL) resistant to permethrin. Cytochrome P450 protein levels of the resistant strains were significantly higher (1.5-fold) than SLAB, but were not significantly different from one another. Expression of CYP4H34 in the larvae and adults of the resistant (ISOP450 and ISOJPAL) and susceptible (SLAB) strains were not statistically different. CYP9M10 was found to be significantly over-expressed in larvae of both permethrin-resistant isogenic strains (1800-fold in ISOP450 and 870-fold in ISOJPAL) when compared to SLAB. Partial sequence analysis of CYP9M10 revealed eight polymorphic sites that distinguished the susceptible allele from the resistant allele. We conclude that CYP9M10 is linked to permethrin resistance in these strains of C. p. quinquefasciatus, and is likely to be the P450 gene responsible for resistance in these strains.

Irbesartan treatment up-regulates hepatic expression of PPARalpha and its target genes in obese Koletsky (fa(k)/fa(k)) rats: a link to amelioration of hypertriglyceridaemia

BACKGROUND AND PURPOSE

Hypertriglyceridaemia is associated with an increased risk of cardiovascular disease. Irbesartan, a well-established angiotensin II type 1 receptor (AT(1)) blocker, improves hypertriglyceridaemia in rodents and humans but the underlying mechanism of action is unclear.

EXPERIMENTAL APPROACH

Male obese Koletsky (fa(k)/fa(k)) rats, which exhibit spontaneous hypertension and metabolic abnormalities, received irbesartan (40 mg x kg(-1) x day(-1)) or vehicle by oral gavage over 7 weeks. Adipocyte-derived hormones in plasma were measured by ELISA. Gene expression in liver and other tissues was assessed by real-time PCR and Western immunoblotting.

KEY RESULTS

In Koletsky (fa(k)/fa(k)) rats irbesartan lowered plasma concentrations of triglycerides and non-esterified fatty acids, and decreased plasma insulin concentrations and the homeostasis model assessment of insulin resistance index. However, this treatment did not affect food intake, body weight, epididymal white adipose tissue weight, adipocyte size and plasma leptin concentrations, although plasma adiponectin was decreased. Irbesartan up-regulated hepatic expression of mRNAs corresponding to peroxisome proliferator-activated receptor (PPAR)alpha and its target genes (carnitine palmitoyltransferase-1a, acyl-CoA oxidase and fatty acid translocase/CD36) that mediate hepatic fatty acid uptake and oxidation; the increase in hepatic PPARalpha expression was confirmed at the protein level. In contrast, irbesartan did not affect expression of adipose PPARgamma and its downstream genes or hepatic genes that mediate fatty acid synthesis.

CONCLUSIONS AND IMPLICATIONS

These findings demonstrate that irbesartan treatment up-regulates PPARalpha and several target genes in liver of obese spontaneously hypertensive Koletsky (fa(k)/fa(k)) rats and offers a novel insight into the lipid-lowering mechanism of irbesartan.

Current spread in the smooth muscle of the guinea-pig vas deferens

1. The membrane polarization in response to intracellular stimulation and external stimulation, the junction potentials evoked by nerve and field stimulation and the spontaneous junction potentials were studied in the guinea-pig vas deferens.2. The responses to intracellular stimulation differed from those to external stimulation applied through a large electrode in the following ways: short time constant of the electrotonic potential; linearity of current-voltage relation; all-or-none spike only in a small proportion of the cells; high critical firing level; short latency; weak tendency for repetitive activity during depolarization; and sharp spatial decay of the response.3. The difference between intracellular and external stimulation could be explained by differences in current distribution in the tissue, if many muscle fibres were aggregated in functional bundles, with three-dimensional cell-to-cell connexions, so that the membrane near an intracellular stimulating electrode was shunted by a large area of surrounding membrane.4. The time course of the junction potentials depended on the manner by which they were produced. The junction potential evoked by hypogastric nerve stimulation was recorded in every cell with almost the same amplitude. The spontaneous junction potential decayed very sharply with distance and the time course of the falling phase was about 10 times faster than that of the evoked junction potential.The difference between the time course of the junction potentials was also explained by the difference in current distribution in the tissue.

TP53 mutations coincide with the ectopic expression of activation-induced cytidine deaminase in the fibroblast-like synoviocytes derived from a fraction of patients with rheumatoid arthritis

Main features of rheumatoid arthritis (RA), hyperplasia of fibroblast-like synoviocytes (FLS) and joint destruction are caused by inflammatory cytokines produced in chronic autoimmune inflammation. Cell-intrinsic acquisition of tumour-like phenotypes of RA-FLS could also be responsible for the aggressive proliferation and invasion, which are supported by the fact that in some cases RA-FLS has mutations of a tumour suppressor gene TP53. However, the underlying molecular mechanism for TP53 mutations in RA-FLS has not yet been clarified. Recently it has been reported that the non-lymphoid cells in the inflammatory tissues express ectopically the activation-induced cytidine deaminase (AID) gene that induces somatic hypermutations, not only at the immunoglobulin (Ig) gene variable regions in germinal centre B lymphocytes but also at coding regions in TP53. Real-time polymerase chain reaction (PCR) analyses revealed more than half (five of nine) of the RA-FLS lines we established showed the markedly increased expression of AID. AID transcription in RA-FLS was augmented by tumour necrosis factor (TNF)-alpha and even by physiological concentration of beta-oestradiol that could not induce AID transcription in osteoarthritis-FLS. Furthermore, AID-positive RA-FLS presented a higher frequency of somatic mutations in TP53. Cytological and immunohistochemical analyses demonstrated clearly the ectopic expression of AID in the FLS at the RA synovium. These data suggested strongly a novel consequence of RA; the ectopic expression of AID in RA-FLS causes the somatic mutations and dysfunction of TP53, leading to acquisition of tumour-like properties by RA-FLS.