Immunopathological Changes in the Brain of Immunosuppressed Mice Experimentally Infected with Toxocara canis

Toxocariasis is a soil-transmitted helminthozoonosis due to infection of humans by larvae of Toxocara canis. The disease could produce cognitive and behavioral disturbances especially in children. Meanwhile, in our modern era, the incidence of immunosuppression has been progressively increasing due to increased incidence of malignancy as well as increased use of immunosuppressive agents. The present study aimed at comparing some of the pathological and immunological alterations in the brain of normal and immunosuppressed mice experimentally infected with T. canis. Therefore, 180 Swiss albino mice were divided into 4 groups including normal (control) group, immunocompetent T. canis-infected group, immunosuppressed group (control), and immunosuppressed infected group. Infected mice were subjected to larval counts in the brain, and the brains from all mice were assessed for histopathological changes, astrogliosis, and IL-5 mRNA expression levels in brain tissues. The results showed that under immunosuppression, there were significant increase in brain larval counts, significant enhancement of reactive gliosis, and significant reduction in IL-5 mRNA expression. All these changes were maximal in the chronic stage of infection. In conclusion, the immunopathological alterations in the brains of infected animals were progressive over time, and were exaggerated under the effect of immunosuppression as did the intensity of cerebral infection.     

N-phenyl ureidobenzenesulfonates,a novel class of promising human dihydroorotate dehydrogenase inhibitors

N-phenyl ureidobenzenesulfonates (PUB-SOs) is a new class of promising anticancer agents inducing replication stresses and cell cycle arrest in S-phase. However, the pharmacological target of PUB-SOs was still unidentified. Consequently, the objective of the present study was to identify and confirm the pharmacological target of the prototypical PUB-SO named 2-ethylphenyl 4-(3-ethylureido)benzenesulfonate (SFOM-0046) leading to the cell cycle arrest in S-phase. The antiproliferative and the cytotoxic activities of SFOM-0046 were characterized using the NCI-60 screening program and its fingerprint was analyzed by COMPARE algorithm. Then, human dihydroorotate dehydrogenase (hDHODH) colorimetric assay, uridine rescuing cell proliferation and molecular docking in the brequinar-binding site were performed. As a result, SFOM-0046 exhibited a mean antiproliferative activity of 3.5 μM in the NCI-60 screening program and evidenced that leukemia and colon cancer cell panels were more sensitive to SFOM-0046. COMPARE algorithm showed that the SFOM-0046 cytotoxic profile is equivalent to the ones of brequinar and dichloroallyl lawsone, two inhibitors of hDHODH. SFOM-0046 inhibited the hDHODH in the low nanomolar range (IC₅₀ = 72 nM) and uridine rescued the cell proliferation of HT-29, HT-1080, M21 and MCF-7 cancer cell lines in the presence of SFOM-0046. Finally, molecular docking showed a binding pose of SFOM-0046 interacting with Met43 and Phe62 present in the brequinar-binding site. In conclusion, PUB-SOs and notably SFOM-0046 are new small molecules hDHODH inhibitors triggering replication stresses and S-phase arrest.     

Physiological function as regulation of large transcriptional programs: the cellular response to genotoxic stress

The responses to ionizing radiation and other genotoxic environmental stresses are complex and are regulated by a number of overlapping molecular pathways. One such stress signaling pathway involves p53, which regulates the expression of over 100 genes already identified. It is also becoming increasingly apparent that the pattern of stress gene expression has some cell type specificity. It may be possible to exploit these differences in stress gene responsiveness as molecular markers through the use of a combined informatics and functional genomics approach. The techniques of microarray analysis potentially offer the opportunity to monitor changes in gene expression across the entire set of expressed genes in a cell or organism. As an initial step in the development of a functional genomics approach to stress gene analysis, we have recently demonstrated the utility of cDNA microarray hybridization to measure radiation-stress gene responses and identified a number of previously unknown radiation-regulated genes. The responses of some of these genes to DNA-damaging agents vary widely in cell lines from different tissues of origin and different genetic backgrounds. While this again highlights the importance of a cellular context to genotoxic stress responses, it also raises the prospect of expression-profiling of cell lines, tissues, and tumors. Such profiles may have a predictive value if they can define regions of ‘expression space’ that correlate with important endpoints, such as response to cancer therapy regimens, or identification of exposures to environmental toxins.     

Investigation of role of aspartame on apoptosis process in HeLa cells -->

Aspartame is an artificial sweetener used as an alternate for sugar in several foods and beverages. The study reports that consumption of aspartame containing product could lead to cancer. However, the effect of aspartame on apoptosis process in cancer is not yet understood clearly. HeLa cells were exposed to different concentrations (0.01–0.05 mg/ml) of aspartame for 48 h. Cytotoxicity of aspartame on cancer cells was determined by SRB assay. The result indicates no significant changes on cell viability. Aspartame suppresses apoptosis process in cancer cells by down-regulation of mRNA expression of tumor suppressor gene p53, and pro-apoptotic gene bax. It up-regulates anti-apoptotic gene bcl-2 mRNA expression. In addition, Ki 67 and PCNA mRNA, and protein expressions were determined. Taking all these together, we conclude that aspartame may be a potent substance to slow-down the apoptosis process in HeLa cells. Further works are ongoing to understand the biochemical and molecular mechanism of aspartame in cancer cells.     

Inhibition of Cell Proliferation and Migration by miR-509-3p That Targets CDK2, Rac1, and PIK3C2A

CDK2 is a key regulator of cell cycle progression. In this study, we screened for miRNAs targeting CDK2 using a luciferase-3′-untranslated region reporter assay. Among 11 hit miRNAs, miR-509-3p reduced CDK2 protein levels and significantly inhibited cancer cell growth. Microarray, Western blotting, and luciferase reporter analyses revealed additional targets of miR-509-3p, including Rac1 and PIK3C2A. Overexpression of miR-509-3p induced G1 cell-cycle arrest and inhibited colony formation and migration. RNAi experiments indicated that the growth-inhibitory effects of miR-509-3p may occur through down-regulation of CDK2, Rac1, and PIK3C2A. Targeting of multiple growth regulatory genes by miR-509-3p may contribute to effective anti-cancer therapy.     

Bone marrow-derived mesenchymal stem cells repair severe acute pancreatitis by secreting miR-181a-5p to target PTEN/Akt/TGF-β1 signaling

BackgroundSevere acute pancreatitis (SAP) is associated with high morbidity and mortality. Bone marrow mesenchymal stem cells (BMSCs) have shown obvious protective effect on SAP. However, little is known about the underlying mechanism. The objective of this study is to unravel the role and regulatory mechanism of miR-181a-5p in BMSCs-mediated pancreatic repair.MethodsBMSCs were isolated from Sprague-Dawley rats and characterized by flow cytometry and Oil Red O staining. Sodium taurocholate- and caerulein-induced models were used as SAP models in vivo and in vitro, respectively. Pancreatic injury were evaluated by H&E and histopathological analysis, as well as by measuring levels of amylase, lipase and cytokines. qRT-PCR and western blotting were performed to detect the level of miR-181a-5p and the protein levels of PTEN/Akt, respectively. ELISA was conducted to detect the levels of TNF-α, IL-1β, IL-6, angiopoietin, IL-4, IL-10 and TGF-β1. The apoptotic rate of AR42 J cells was quantitated by concurrent staining with Annexin-V-FITC and PI.ResultsBMSCs significantly attenuated pancreatic injury in SAP rats by reducing inflammatory infiltration and necrosis, and this effect was abolished by CXCR4 agonist AMD3100. ADM3100 exhibited more severe pancreatic injury and decreased miR-181a-5p levels in the pancreas and serum compared to SAP group. Overexpression of miR-181a-5p in BMSCs (BMSCs-miR-181a-5p) markedly potentiated the protective effect of BMSCs by reducing histological damage and levels of amylase and lipase. Moreover, BMSCs-miR-181a-5p dramatically reduced levels of angiopoietin, TNF-α, IL-1β and IL-6, but induced the levels of IL-4 and IL-10. In caerulein-treated AR42 J cells, co-culturing of BMSCs-miR-181a-5p alleviated caerulein-induced increase of amylase and lipase, and apoptosis via PTEN/Akt/TGF-β1 signaling.ConclusionBMSCs alleviate SAP and reduce inflammatory responses and apoptosis by secreting miR-181a-5p to target PTEN/Akt/TGF-β1 signaling. Hence, BMSCs-miR-181a-5p could serve as potential therapeutic target for SAP.     

Accuracies in Po-210 determination for lead-210 dating

Various laboratory techniques have been utilized worldwide for measuring lead-210 in sub-recent deposits through its grand-daughter product polonium-210. Isotope dilution alpha spectrometry proved a suitable tool for absolute determination of lead-210 for the dating of aquatic deposits. Moreover, isotope dilution alpha spectrometry along with speciation experiments can be used to resolve depositional anomalies arising from supported lead-210/Ra-226 disequilibrium levels and unsupported lead-210 mobile fractions. Isotope dilution alpha spectrometry of sub-recent sediment and peat deposits has been critically evaluated for more than ten years. Our results show that type, size and composition of deposits analyzed as well as radiochemical procedures used, together with alpha counting techniques, are important factors influencing lead-210 determinations and tailing corrections using its granddaughter product polonium-210. Optimization of these parameters is of prime importance to achieve economic and accurate analyses, especially at low lead-210 concentrations and small sample sizes.     

溶血磷脂酸在皮肤损伤疾病中的作用及其分子机制

皮肤作为人体最大器官覆盖于全身,能阻挡有害物质的侵入,保护人体内环境稳态,参与人体代谢过程。皮肤损伤、炎症和纤维化等,都会导致皮肤屏障功能的减退,影响正常的生命活动。溶血磷脂酸(lysophosphatidic acid,LPA)是十分活跃的磷脂信号分子,参与多种生理和病理生理过程。LPA是维持体内平衡所必需的生物活性脂质介质,在皮肤中通过不同的信号通路发挥多功能磷脂信使作用。本文综述了皮肤中溶血磷脂酸受体(lysophosphatidic acid receptor,LPA1-6)及其细胞信号通路的作用及机制,综述了LPA在皮肤创面愈合、皮肤瘢痕、皮肤黑色素瘤、硬皮病、皮肤瘙痒、过敏性皮炎、皮肤屏障、皮肤疼痛,皮肤毛发生长中的作用及分子机制,有助于了解LPA在皮肤中的生理和病理生理作用。深入研究LPA的作用机制将有助于挖掘其在皮肤治疗中的作用,开发以LPA为靶点的药物。