Retroviral transfer of the p16INK4a cDNA inhibits C6 glioma formation in Wistar rats

BACKGROUND: The p16(INK4A) gene product halts cell proliferation by preventing phosphorylation of the Rb protein. The p16INK4a gene is often deleted in human glioblastoma multiforme, contributing to unchecked Rb phosphorylation and rapid cell division. We show here that transduction of the human p16INK4a cDNA using the pCL retroviral system is an efficient means of stopping the proliferation of the rat-derrived glioma cell line, C6, both in tissue culture and in an animal model. C6 cells were transduced with pCL retrovirus encoding the p16INK4a, p53, or Rb genes. These cells were analyzed by a colony formation assay. Expression of p16INK4a was confirmed by immunohistochemistry and Western blot analysis. The altered morphology of the p16-expressing cells was further characterized by the senescence-associated β-galactosidase assay. C6 cells infected ex vivo were implanted by stereotaxic injection in order to assess tumor formation. RESULTS: The p16INK4a gene arrested C6 cells more efficiently than either p53 or Rb. Continued studies with the p16INK4a gene revealed that a large portion of infected cells expressed the p16INK4a protein and the morphology of these cells was altered. The enlarged, flat, and bi-polar shape indicated a senescence-like state, confirmed by the senescence-associated β-galactosidase assay. The animal model revealed that cells infected with the pCLp16 virus did not form tumors. CONCLUSION: Our results show that retrovirus mediated transfer of p16INK4a halts glioma formation in a rat model. These results corroborate the idea that retrovirus-mediated transfer of the p16INK4a gene may be an effective means to arrest human glioma and glioblastoma

Response of Foraminifera to Anthropogenic Nicotine Pollution of Cigarette Butts: An Experimental Approach

The most often dispersed environmental pollutants that are released both directly and indirectly into the environment that may eventually reach aquatic ecosystems and contaminate aquatic biomes are cigarette butts (CBs). Toxicants such as nicotine, dangerous metals, total particulate matter, and recognized carcinogens can be introduced and transported via CBs into aquatic ecosystems. The examination of the effects of synthetic nicotine on three different species of cultured benthic foraminifera was the focus of this study. Three foraminiferal species from three distinct biomineralization pathways were specifically examined for viability and cellular ultrastructure, including the calcareous perforate Rosalina globularis, the calcareous imperforate Quinqueloculina spp., and the agglutinated Textularia agglutinans. The survival rate, cellular stress, and decalcification were used to assess the toxicological effects of synthetic nicotine. We were able to analyze the reaction of major macromolecules and calcium carbonate to this pollutant using FTIR (Fourier Transform Infrared) spectroscopy. High Performance Liquid Chromatography (HPLC) study was performed to increase our understanding of nicotine bioavailability in the medium culture. Different acute experiments were performed at different dates, and all indicated that synthetic nicotine is acutely hazardous to all three cultured foraminiferal taxa at lethal and sublethal concentrations. Each species responded differently depending on the type of shell biomineralization. Synthetic nicotine enhances shell decalcification and affects the composition of cytoplasmic macromolecules such as lipids and proteins, according to the FTIR spectroscopy investigations. The lipid content rose at lethal concentrations, possibly due to the creation of vesicles. The proteins signal evidences general cellular dyshomeostasis. The integration among the acute toxicity assay, synchrotron, and chemical HPLC analyses provided a valuable approach for the assessment of nicotine as a biomarker of exposure to the toxicants associated with smoking and the impact of this emerging and hazardous material on calcifying marine species

Methylglyoxal, Glycated Albumin, PAF, and TNF-α: Possible Inflammatory and Metabolic Biomarkers for Management of Gestational Diabetes

Background: In gestational diabetes mellitus (GDM), pancreatic \u3b2-cell breakdown can result from a proinflammatory imbalance created by a sustained level of cytokines. In this study, we investigated the role of specific cytokines, such as B-cell activating factor (BAFF), tumor necrosis factor \u3b1 (TNF-\u3b1), and platelet-activating factor (PAF), together with methylglyoxal (MGO) and glycated albumin (GA) in pregnant women affected by GDM. Methods: We enrolled 30 women whose inflammation and metabolic markers were measured at recruitment and after 12 weeks of strict dietetic therapy. We compared these data to the data obtained from 53 randomly selected healthy nonpregnant subjects without diabetes, hyperglycemia, or any condition that can affect glycemic metabolism. Results: In pregnant women affected by GDM, PAF levels increased from 26.3 (17.4-47.5) ng/mL to 40.1 (30.5-80.5) ng/mL (p < 0.001). Their TNF-\u3b1 levels increased from 3.0 (2.8-3.5) pg/mL to 3.4 (3.1-5.8) pg/mL (p < 0.001). The levels of methylglyoxal were significantly higher in the women with GDM (p < 0.001), both at diagnosis and after 12 weeks (0.64 (0.46-0.90) \u3bcg/mL; 0.71 (0.47-0.93) \u3bcg/mL, respectively) compared to general population (0.25 (0.19-0.28) \u3bcg/mL). Levels of glycated albumin were significantly higher in women with GDM (p < 0.001) only after 12 weeks from diagnosis (1.51 (0.88-2.03) nmol/mL) compared to general population (0.95 (0.63-1.4) nmol/mL). Conclusion: These findings support the involvement of new inflammatory and metabolic biomarkers in the mechanisms related to GDM complications and prompt deeper exploration into the vicious cycle connecting inflammation, oxidative stress, and metabolic results

Impact of N-tau on adult hippocampal neurogenesis, anxiety, and memory.

Different pathological tau species are involved in memory loss in Alzheimer’s disease, the most common cause of dementia among older people. However, little is known about how tau pathology directly affects adult hippocampal neurogenesis, a unique form of structural plasticity implicated in hippocampusdependent spatial learning and mood-related behavior. To this aim, we generated a transgenic mouse model conditionally expressing a pathological tau fragment (26e230 aa of the longest human tau isoform, or N-tau) in nestin-positive stem/progenitor cells. We found that N-tau reduced the proliferation of progenitor cells in the adult dentate gyrus, reduced cell survival and increased cell death by a caspase- 3eindependent mechanism, and recruited microglia. Although the number of terminally differentiated neurons was reduced, these showed an increased dendritic arborization and spine density. This resulted in an increase of anxiety-related behavior and an impairment of episodic-like memory, whereas less complex forms of spatial learning remained unaltered. Understanding how pathological tau species directly affect neurogenesis is important for developing potential therapeutic strategies to direct neurogenic instructive cues for hippocampal function repair

Axonal Odorant Receptors Mediate Axon Targeting

In mammals, odorant receptors not only detect odors but also define the target in the olfactory bulb, where sensory neurons project to give rise to the sensory map. The odorant receptor is expressed at the cilia, where it binds odorants, and at the axon terminal. The mechanism of activation and function of the odorant receptor at the axon terminal is, however, still unknown. Here, we identify phosphatidylethanolamine- binding protein 1 as a putative ligand that activates the odorant receptor at the axon terminal and affects the turning behavior of sensory axons.Genetic ablation of phosphatidylethanolamine-binding protein 1 in mice results in a strongly disturbed olfactory sensory map. Our data suggest that the odorant receptor at the axon terminal of olfactory neurons acts as an axon guidance cue that responds to molecules originating in the olfactory bulb. The dual function of the odorant receptor links specificity of odor perception and axon targeting

2- and 8-alkynyl-9-ethyladenines: Synthesis and biological activity at human and rat adenosine receptors

The synthesis of a series of 9-ethyladenine derivatives bearing alkynyl chains in 2- or 8-position was undertaken, based on the observation that replacement of the sugar moiety in adenosine derivatives with alkyl groups led to adenosine receptor antagonists. All the synthesized compounds were tested for their affinity at human and rat A1, A2A, and A3 adenosine receptors in binding assays; the activity at the human A2B receptor was determined in adenylyl cyclase experiments. Biological data showed that the 2-alkynyl derivatives possess good affinity and are slightly selective for the human A2A receptor. The same compounds tested on the rat A1 and A2A subtypes showed in general lower affinity for both receptors. On the other hand, the affinity of the 8-alkynyl derivatives at the human A1, A2A, and A2B receptors proved to be lower than that of the corresponding 2-alkynyl derivatives. On the contrary, the affinity of the same compounds for the human A3 receptor was improved, resulting in A3 selectivity. As in the case of the 2-alkynyl-substituted compounds, the 8-alkynyl derivatives showed decreased affinity for rat receptors. However, it is worthwhile to note that the 8-phenylethynyl-9-ethyladenine was the most active compound of the two series (Ki in the nanomolar range) at both the human and rat A3 subtype. Docking experiments of the 2- and 8-phenylethynyl-9-ethyladenines, at a rhodopsin-based homology model, gave a rational explanation of the preference of the human A3 receptor for the 8-substituted compound