Drosophila olfactory local interneurons and projection neurons derive from a common neuroblast lineage specified by the empty spiracles gene

Background

The skeletal neuromuscular junction is a useful model for elucidating mechanisms that regulate synaptogenesis. Developmentally important intercellular interactions at the neuromuscular junction are mediated by the synaptic portion of a basal lamina that completely ensheaths each muscle fiber. Basal laminas in general are composed of four main types of glycosylated proteins: laminins, collagens IV, heparan sulfate proteoglycans and nidogens (entactins). The portion of the muscle fiber basal lamina that passes between the motor nerve terminal and postsynaptic membrane has been shown to bear distinct isoforms of the first three of these. For laminins and collagens IV, the proteins are deposited by the muscle; a synaptic proteoglycan, z-agrin, is deposited by the nerve. In each case, the synaptic isoform plays key roles in organizing the neuromuscular junction. Here, we analyze the fourth family, composed of nidogen-1 and -2.

Results

In adult muscle, nidogen-1 is present throughout muscle fiber basal lamina, while nidogen-2 is concentrated at synapses. Nidogen-2 is initially present throughout muscle basal lamina, but is lost from extrasynaptic regions during the first three postnatal weeks. Neuromuscular junctions in mutant mice lacking nidogen-2 appear normal at birth, but become topologically abnormal as they mature. Synaptic laminins, collagens IV and heparan sulfate proteoglycans persist in the absence of nidogen-2, suggesting the phenotype is not secondary to a general defect in the integrity of synaptic basal lamina. Further genetic studies suggest that synaptic localization of each of the four families of synaptic basal lamina components is independent of the other three.

Conclusion

All four core components of the basal lamina have synaptically enriched isoforms. Together, they form a highly specialized synaptic cleft material. Individually, they play distinct roles in the formation, maturation and maintenance of the neuromuscular junction.     

Apoptotic cells induce Mer tyrosine kinase-dependent blockade of NF-kappaB activation in dendritic cells

Dendritic cells (DCs) play a key role in immune homeostasis and maintenance of self-tolerance. Tolerogenic DCs can be established by an encounter with apoptotic cells (ACs) and subsequent inhibition of maturation and effector functions. The receptor(s) and signaling pathway(s) involved in AC-induced inhibition of DCs have yet to be defined. We demonstrate that pretreatment with apoptotic but not necrotic cells inhibits activation of IkappaB kinase (IKK) and downstream NF-kappaB. Notably, receptor tyrosine kinase Mer (MerTK) binding of ACs is required for mediating this effect. Monocyte-derived DCs lacking MerTK expression (MerTKKD) or treated with blocking MerTK-specific antibodies (Abs) are resistant to AC-induced inhibition and continue to activate NF-kappaB and secrete proinflammatory cytokines. Blocking MerTK activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway prevents AC-induced inhibition. These results demonstrate an essential role for MerTK-mediated regulation of the PI3K/AKT and NF-kappaB pathways in AC-induced inhibition of monocyte-derived DCs.     

Role of apoptotic regulators in human epithelial ovarian cancer

We assessed molecular markers such as BRCA1, K-ras, p53, Bcl-2, Bcl-XL, Survivin and telomerase activity in untreated ovarian cancer tissue samples, ascitic cells and normal ovarian tissues and gathered insights into their correlation with each other and also with apoptotic index. The expression of these proteins was analyzed by Western blotting and immunohistochemistry. Apoptotic index was determined by TUNEL assay and telomerase activity was measured by PCR-ELISA kit. p53, Bcl-2, Bcl-XL, K-ras and Survivin were found to be over expressed in tumors and ascitic cells as compared to normal controls whereas there was no significant difference in expression of BRCA1. A significantly higher telomerase activity and lower apoptotic index in tumors as compared to controls was observed. p53 positively correlated with Bcl-2, Bcl-XL, K-ras and Survivin expression and also clinical stage of the disease. A positive correlation between Survivin and Bcl-2, Bcl-XL was seen. Apoptotic Index, telomerase activity and BRCA1 expression showed no correlation with any of the parameters. Our study confirms the fact that multiple gene interactions govern the pathogenesis of ovarian cancer, and analyzing ascitic cells of ovarian cancer patients may help to delineate molecular profile of the primary tumor.     

Association between Aurora-A kinase polymorphisms and age of onset of hereditary nonpolyposis colorectal cancer in a Caucasian population

Aurora-A kinase is considered a potential cancer susceptibility gene that encodes a centrosome-associated, cell cycle-regulated serine/threonine kinase. We studied two single nucleotide polymorphisms (SNP) in the coding region of Aurora-A, 91T-to-A (F31I) and 169G-to-A (V57I). We studied the influence of these two polymorphisms on age of onset of hereditary nonpolyposis colorectal cancer (HNPCC). Genotyping of the Aurora-A polymorphisms was carried out on 125 Caucasian with mismatch repair (MMR) gene mutations with real-time pyrophosphate DNA sequencing. For the 91T-to-A polymorphism, we found that patients with HNPCC who were homozygous for the wild-type allele developed colorectal cancer (CRC) 7 years earlier than patients who were homozygous or heterozygous for the mutant allele. The169G-to-A polymorphism did not have a significant influence on risk for HNPCC. However, when we did haplotype analysis for these two polymorphisms, the 91A-169G haplotype was associated with protection from HNPCC at an earlier age.     

Evaluation of sexual function in women with overactive bladder syndrome

INTRODUCTION: Of late, little data is available concerning factors affecting female sexual function. In the present study, we evaluated the effects of overactive bladder (OAB) syndrome symptoms on female sexual function. MATERIALS AND METHODS: 40 patients with OAB symptoms and 40 age-matched women as a control group were evaluated using the Female Sexual Function Index (FSFI) for sexual function. According to the presence of urge incontinence, women with OAB were also divided into wet and dry groups. After completion of the forms, groups were compared. RESULTS: Although scores of all domains of FSFI (desire, arousal, lubrication, orgasm, satisfaction, pain and total) in the OAB group were found to be lower than in the control group, only 'desire' was found to be significantly different (p = 0.035). The FSFI scores of the OAB-dry and OAB-wet group were similar to each other. CONCLUSION: The results indicate that there is a trend toward lower sexual function scores in women with OAB compared to controls.     

Indirect role of α<Subscript>2</Subscript>-adrenoreceptors in anti-ulcer effect mechanism of nimesulide in rats

Nimesulide, a non-steroidal, anti-inflammatory drug, produces ulcerogenic effects in adrenalectomized rats but is gastro-protective in intact rats. The objective of this study was to determine whether adrenal gland hormones are involved in the anti-ulcer effects of nimesulide. The results revealed that 100 mg/kg nimesulide produces gastric ulceration in adrenalectomized rats, which is prevented by prednisolone and adrenaline. The anti-ulcer effects of adrenaline and prednisolone in adrenalectomized rats were in turn antagonized by yohimbine, a selective α₂-receptor blocker, but not by doxazosine (α₁-receptor blocker) or propranolol (β-blocker). Adrenaline prevented the formation of indomethacin-induced ulcers in both adrenalectomized and intact rats, but prednisolone increased the indomethacin-induced ulcerous area in intact rats, whereas it decreased the size of the ulcers in adrenalectomized rats. In addition, prednisolone prevented ulcer formation in intact rats in which the adrenaline concentration had been decreased by metyrosine. These results suggest that glucocorticoids are anti-ulcerogenic in not only adrenalectomized rats but also in intact rats with diminished circulating levels of adrenaline. In the light of these data, the effect of nimesulide on plasma adrenaline concentrations was studied. In comparison to the adrenaline levels found in intact control rats, the administration of nimesulide at doses of 10, 20, 40 and 100 mg/kg decreased adrenaline concentrations by 12.8, 22.6, 30.4, and 58.2%, respectively, without affecting blood corticosterone concentrations. The anti-ulcer effect of nimesulide was observed to be dose-dependent, and the strength of this effect was directly correlated the decreasing concentration of adrenaline. The concentration of adrenaline was decreased by 60.9% in rats treated with 300 mg/kg metyrosine in which prednisolone produced anti-ulcer effects. In summary, we have shown that nimesulide produces its anti-ulcer effect by decreasing endogenous adrenaline concentrations and that glucocorticoids may induce anti-ulcer effects via α₂-adrenoreceptors, but not via their own receptors. This research was conducted in the Laboratory of Pharmacology at Ataturk University, Faculty of Medicine, Department of Pharmacology, 25240 Erzurum/Turkey.     

Trichloroethylene induce nitric oxide production and nitric oxide synthase mRNA expression in cultured normal human epidermal keratinocytes

Trichloroethylene (TCE), a major chemical hazard during occupational exposure, can cause obvious skin lesions, including irritant reactions and dermatitis. Nitric oxide (NO) synthesized by nitric oxide synthase (NOS) is involved in a broad array of pathogenesis of skin inflammatory and immune responses. To understand the mechanisms of TCE-induced dermatoxicity, we investigated the effects of TCE on NO production and NOS mRNA expression in cultured normal human epidermal keratinocytes (NHEK). Cells were treated with TCE (0 mM, 0.125 mM, 0.25 mM, 0.5 mM, 1.0 mM, 2.0 mM) for 4 h, and then incubated for 12 h, 24 h, 48 h and 72 h. At each given time point, NO production were evaluated indirectly by measuring nitrite plus nitrate concentration in the culture medium using Griess reaction, as well as cell viability determined by MTT test, iNOS and cNOS activities assayed with a NOS activity detecting kit. The expression of iNOS and cNOS mRNA was detected using RT-PCR. TCE decreases cell viability and enhance NO production from NHEK in concentration- and time-dependent manner. Aminoguanidine (AG), an inhibitor of NOS, can prevent NO production and cell viability decrease in NHEK by TCE induced. Change to NO production was accompanied by increased activities of both types of NOS, but the iNOS activity accounted mainly for the TCE-induced NO production. RT-PCR detection showed that NHEK expressed both iNOS and cNOS mRNA by TCE exposure. Whereas a concentration- and time-dependent up-regulation of the mRNA expression was observed for iNOS and cNOS following TCE exposure, changes to iNOS were more marked. These results suggest that TCE caused increase in NO production, attributed to activation of iNOS as well as cNOS, and expression of iNOS and cNOS mRNA. These cellular changes may contribute to the pathological and physiological features of TCE-induced erythema and skin inflammation.