Brain changes associated with thromboxane receptor antagonist SQ 29,548 treatment in a mouse model

The purpose of this study was to characterize behavioral and physiological effects of a selective thromboxane (TP) receptor antagonist, SQ 29,548, in the C57Bl/6 mouse model. At 6 months of age, male mice were given either sham or drug i.p. injections for 3 days at a dose of 2 mg/kg each day. On the day after the final injection, mice were subjected to behavioral testing before brain collection. Left hemisphere hippocampi were collected from all mice for protein analysis via Western blot. Right brain hemispheres were fixed and embedded in gelatin and then serially sectioned. The sections were immunostained with anti‐c‐Fos antibodies. Prostaglandin analysis was performed from remaining homogenized brain samples, minus the hippocampi. Injection of SQ 29,548 decreased selective brain prostaglandin levels compared with sham controls. This correlated with robust increases in limbic‐region c‐Fos immunoreactivity in the SQ 29,548‐injected mice. However, drug‐treated mice demonstrated no significant changes in relevant hippocampal protein levels compared with sham treatments, as determined from Western blots. Surprisingly, injection of SQ 29,548 caused mixed changes in parameters of depression and anxiety‐like behavior in the mice. In conclusion, the results indicate that administration of peripheral TP receptor antagonists alters brain levels of prostanoids and influences neuronal activity, with only minimal alterations of behavior. Whether the drug affects neurons directly or through a secondary pathway involving endothelium or other tissues remains unclear. © 2015 Wiley Periodicals, Inc.     

Anaphylaxis in the United States: an investigation into its epidemiology

BACKGROUND: Anaphylaxis is a severe, life-threatening allergic reaction that affects both children and adults in the United States. However, data regarding the incidence and prevalence of anaphylaxis and the number of deaths caused by it are limited. OBJECTIVE: To provide a better understanding of the magnitude of the problem of anaphylaxis in the United States. METHODS: A thorough review of the current medical literature was conducted to obtain prevalence estimates on each of the 4 major subtypes of anaphylaxis (food, drugs, latex, and insect stings). We calculated an overall estimate of the risk of anaphylaxis by using only estimates that are specifically derived from epidemiologic studies measuring anaphylaxis in the general population. RESULTS: Known rates or cases of anaphylaxis were 0.0004% for food, 0.7% to 10% for penicillin, 0. 22% to 1% for radiocontrast media, and 0.5% to 5% after insect stings. There were 220 cases after latex exposure. Considering the 1999 US population of 272 million, the population at risk for anaphylaxis from food is 1099, from penicillin is 1.9 million to 27. 2 million, from radiocontrast media is 22 000 to 100 000, from latex is 220, and from insect stings is 1.36 million to 13.6 million. These calculations yield a total of 3.29 million to 40.9 million individuals at risk of anaphylaxis. CONCLUSION: The occurrence of anaphylaxis in the US is not as rare as is generally believed. On the basis of our figures, the problem of anaphylaxis may, in fact, affect 1.21% to 15.04% of the US population.     

Microbial Biomass and Activity in Relation to Accessibility of Organic Carbon in Saline Soils of Coastal Agro-Ecosystem

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - In coastal agro-ecosystems, soil salinity follows a decreasing gradient from coastal margin towards inland...     

Autophagy is required for proper cysteine homeostasis in pancreatic cancer through regulation of SLC7A11

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest forms of cancer and is highly refractory to current therapies. We had previously shown that PDAC can utilize its high levels of basal autophagy to support its metabolism and maintain tumor growth. Consistent with the importance of autophagy in PDAC, autophagy inhibition significantly enhances response of PDAC patients to chemotherapy in two randomized clinical trials. However, the specific metabolite(s) that autophagy provides to support PDAC growth is not yet known. In this study, we demonstrate that under nutrient-replete conditions, loss of autophagy in PDAC leads to a relatively restricted impairment of amino acid pools, with cysteine levels showing a significant drop. Additionally, we made the striking discovery that autophagy is critical for the proper membrane localization of the cystine transporter SLC7A11. Mechanistically, autophagy impairment results in the loss of SLC7A11 on the plasma membrane and increases its localization at the lysosome in an mTORC2-dependent manner. Our results demonstrate a critical link between autophagy and cysteine metabolism and provide mechanistic insights into how targeting autophagy can cause metabolic dysregulation in PDAC.

Despite progress in cancer therapy, the prognosis for pancreatic ductal adenocarcinoma (PDAC) remains extremely poor with a 5-y survival rate of just 9% and it is predicted to become the second leading cause of cancer death in the United States by 2030 (1–3). The PDAC tumor microenvironment is highly desmoplastic and is composed of heterogeneous cell types, as well as an exuberant extracellular matrix. Together, this leads to poor perfusion and extreme hypoxia, creating a nutrient-limited environment with impaired drug penetration (4, 5). Another hallmark of PDAC is elevated basal autophagy which plays multiple protumorigenic roles, including promoting immune evasion and supporting its metabolic demand in this austere microenvironment (6–10). Therefore, clinical strategies have been employed to inhibit autophagy in PDAC patients using lysosomal inhibitors such as chloroquine or hydroxychloroquine (11, 12).While autophagy can support diverse metabolic processes through the degradation of various cargo, how it supports PDAC metabolism has not been fully elucidated. In the present study, we found that autophagy has a selective role in sustaining cysteine (Cys) pools in PDAC. One of the major mechanisms of Cys homeostasis is through the import of cystine (the oxidized dimer of cysteine) through system x_c⁻, a cystine/glutamate antiporter composed of SLC7A11 (xCT) and SLC3A2 (13). Recently, it was shown that both Cys and SLC7A11 are critical for PDAC growth (14). Here, we report that under low Cys conditions, SLC7A11 utilizes autophagy machinery to allow localization at the plasma membrane. Moreover, we demonstrate that loss of autophagy increases phosphorylation of SLC7A11 by mTORC2, and it remains primarily localized at the lysosome where its cystine import function is impaired. In summary, we identify a mechanism of Cys homeostasis in PDAC where the function of SLC7A11 is coordinately sustained by autophagic machinery and mTORC2 activity based on intracellular Cys levels.     

Role of surface charge and wettability on early stage mineralization and bone cell–materials interactions of polarized hydroxyapatite

Our objective was to determine the role of surface charge and wettability on early stage mineralization as well as bone cell adhesion and proliferation on polarized HAp surface. To estimate the surface wettability, contact angles were measured in water, simulated body fluid (SBF) and Dulbecco’s modified Eagle’s medium/nutrient mixture F-12 Ham (DMEM). Experimental results show that HAp surface wettability and surface energy can be tailored by inducing surface charge without introducing any volumetric effects in the material. Increasing the surface charge increased the wettability and also the energy of HAp surfaces in all tested media. A maximum surface energy of 49.47 ± 3.76 mJ/m² was estimated for positively charged HAp surfaces polarized at 400 ^oC. The in vitro bioactivity of polarized HAp samples was evaluated by soaking in SBF and DMEM (cell media). Cell–materials interaction was studied by culturing with human fetal osteoblast cells (hFOB). In vitro results show that tailoring the combined effect of wettability and charge polarity on the HAp surface enable differential binding of inorganic ions (e.g., Ca²⁺, Cl^?, Na⁺, HCO₃^? etc) and organic cell adhesive proteins (e.g., fibronectin, vitronectin etc) with different surface properties, which results in accelerated or decelerated mineralization as well as cell adhesion and proliferation on polarized HAp surface.     

Mitochondrial oxidative stress and permeability transition in isoniazid and rifampicin induced liver injury in mice

BACKGROUND/AIMS: To evaluate the role of mitochondrial oxidative stress and permeability transition (MPT) in isoniazid (INH) and rifampicin (RMP) induced hepatotoxicity in mice. METHODS: Liver damage was induced by co-treatment of INH (50 mg/kg) and RMP (100 mg/kg). Pre-treatment with either methionine or phorone was done to modulate hepatic GSH level. Liver cell injury was assessed biochemically and histologically.Evidence of apoptosis was sought by TUNEL test, caspase assay and histology. RESULTS: INH and RMP co-treatment caused steatosis and increased apoptosis of the hepatocytes, hepatic oxidative stress, particularly in the mitochondrial fraction with increased mitochondrial permeability transition (MPT).Mitochondrial oxidative stress as well as liver cell injury was increased by prior treatment with phorone. This was attenuated by pretreatment with methionine suggesting a glutathione (GSH) dependent phenomenon. CONCLUSIONS: Oxidative stress in the mitochondria and inappropriate MPT are important in the pathogenesis of apoptotic liver cell injury in INH-RMP hepatotoxicity. The phenomenon is GSH dependent and methionine supplementation might have a protective role.     

Abrus agglutinin suppresses human hepatocellular carcinoma in vitro and in vivo by inducing caspase- mediated cell death

Aim： Abrus agglutinin （AGG） from the seeds of Indian medicinal plant Abrus precatorius belongs to the class II ribosome inactivating protein family. In this study we investigated the anticancer effects of AGG against human hepatocellular carcinoma in vitro and in vivo.
Methods： Cell proliferation, DNA fragmentation, Annexin V binding, immunocytofluorescence, Western blotting, caspase activity assays and luciferase assays were performed to evaluate AGG in human liver cancer cells HepG2. Immunohistochemical staining and TUNEL expression were studied in tumor samples of HepG2-xenografted nude mice.
Results： AGG induced apoptosis in HepG2 cells in a dose- and time-dependent manner. AGG-treated HepG2 cells demonstrated an increase in caspase 3/7, 8 and 9 activities and a sharp decrease in the Bcl-2/Bax ratio, indicating activation of a caspase cascade. Co-treatment of HepG2 cells with AGG and a caspase inhibitor or treatment of AGG in Bax knockout HepG2 cells decreased the caspase 3/7 activity in comparison to HepG2 cells exposed only to AGG. Moreover, AGG decreased the expression of Hsp90 and suppressed Akt phosphorylation and NF-κB expression in HepG2 cells. Finally, AGG treatment significantly reduced tumor growth in nude mice bearing HepG2 xenografts, increased TUNEL expression and decreased CD-31 and Ki-67 expression compared to levels observed in the untreated control mice bearing HepG2 cells.
Conclusion： AGG inhibits the growth and progression of HepG2 cells by inducing caspase-mediated cell death. The agglutinin could be an alternative natural remedy for the treatment of human hepatocellular carcinomas.