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The development of normal lung tissue toxicity after radiation exposure results from multiple changes in cell signaling and communication initiated at the time of the ionizing event. The onset of gross pulmonary injury is preceded by tissue hypoxia and chronic oxidative stress. We have previously shown that development of debilitating lung injury can be mitigated or prevented by administration of AEOL10150, a potent catalytic antioxidant, 24 h after radiation. This suggests that hypoxia-mediated signaling pathways may play a role in late radiation injury, but the exact mechanism remains unclear. The purpose of this study was to evaluate changes in the temporal expression of hypoxia-associated genes in irradiated mouse lung and determine whether AEOL10150 alters expression of these genes. A focused oligo array was used to establish a hypoxia-associated gene expression signature for lung tissue from sham-irradiated or irradiated mice treated with or without AEOL10150. Results were further verified by RT-PCR. Forty-four genes associated with metabolism, cell growth, apoptosis, inflammation, oxidative stress, and extracellular matrix synthesis were upregulated after radiation. Elevated expression of 31 of these genes was attenuated in animals treated with AEOL10150, suggesting that expression of a number of hypoxia-associated genes is regulated by early development of oxidative stress after radiation. Genes identified herein could provide insight into the role of hypoxic signaling in radiation lung injury, suggesting novel therapeutic targets, as well as clues to the mechanism by which AEOL10150 confers pulmonary radioprotection.

To investigate the involvement of the nucleus accumbens (NAc) in cognitive impairment and the therapeutic effects of brain-derived neurotrophic factor (BDNF) in an animal model of cognitive deficit, we infused BDNF into the NAc of cognitively impaired aged rats. Cognition was evaluated by Morris water maze test. Structural synaptic plasticity was measured by Golgi staining. Brain tissue homogenization was used to measure the changes in signal molecules. Cultured PC-12 cells expressing tyrosine kinase receptor (Trk) B/p75 neurotrophin receptor (p75 NTR ), p75 NTR or TrkA/p75 NTR receptors were used for BDNF stimulation assays. Significant decreases in the levels of BDNF, phosphatidylinositol-3-kinase (PI3K) and integrin-linked kinase (ILK) activity, protein kinase B (Akt) Ser 473 phosphorylation, dendritic branching, and density of dendritic spines on medium spiny neurons were observed in the NAc. Importantly, infusion of BDNF restored cognition, synaptic plasticity, and cell signaling. In cultured PC-12 cells, BDNF activated PI3K/Akt signaling through the TrkB receptor, whereas stimulation of ILK/Akt occurred through TrkA/p75 NTR heteroreceptor. Our study suggested that the decreased BDNF level and its downstream signaling as well as loss of synaptic plasticity in the NAc are associated with cognitive impairments in aged rats. The BDNF-activated PI3K-Akt and ILK-Akt signaling play a key role in structural synaptic plasticity. Our study also suggested that BDNF could be a mechanism-based treatment for dementia.

Nonferrous mining activities are some of the largest sources of heavy metals emissions into the environment and China is one of the largest producers and consumers of lead and zinc in the world. The cumulative productions and emissions of lead and zinc from mining-related activities in China were estimated. Up to 2007, the cumulative productions of lead and zinc in China were estimated to be about 6.69 and 12.59 Mt, respectively; and about 1.62 Mt lead and 3.32 Mt zinc emitted into the ambient environment during the mining, processing and smelting activities, representing 24.39% and 26.36% cumulative production, respectively. Among these three types of mining-related activities, mineral processing contributes the most to the total emission of 50.67% lead and 45.51% zinc.

Depression is a common mental disorder; however, its molecular mechanism has not been fully elucidated. In this study, we investigated the role of maternal deprivation (MD) and chronic mild stress (CMS) in the pathogenesis of depression in rat models. The mRNA levels of prostate apoptosis response-4 (Par-4) and dopamine receptor D2 (DRD2) genes in the striatum were measured by real-time PCR. Methylation level in the promoter of Par-4 gene was detected by bisulfite sequencing. Correlation between gene expression and depression-like behaviors were analyzed. Our results demonstrated that MD and CMS alone or their combination (dual stresses: DS) caused depression-like behaviors in rats. The mRNA levels of Par-4 and DRD2 genes in the striatum were significantly lower in MD-, CMS-, and DS-treated rats than in control rats. Importantly, Par-4 and DRD2 mRNA levels significantly correlated with depression-like behaviors. However, no significant differences in total methylation levels in the promoter of Par-4 gene were found between four groups. Our study suggested that either maternal deprivation or chronic mild stress plays a crucial role in the development of depression-like behaviors in rats. This process is associated with down-regulated Par-4 and DRD2 gene expression in the striatum through a non-methylation mechanism.

In this study we established conditional silencing of integrin-linked kinase (ILK) expression in Sprague-Dawley rat brain by microinjection of rAAV-2-carrying, Tet-On-regulated siRNA expression cassette into nucleus accumbens (NAc) core and induction with doxycycline. We demonstrated that inhibition of ILK expression was effectively induced by administration of doxycycline for 2 weeks while ILK expression was restored after withdrawing doxycycline for 8 days. Increases in GFAP and OX42 expression were observed 5 weeks post virus injection. Importantly, inhibition of ILK expression in the NAc core had no significant effect on cell apoptosis and animal basal locomotion and stereotypical behaviors, but decreased dendritic density of medium spiny neurons. Our studies suggest that: (1) rAAV-delivered Tet-On-regulated siRNA expression can conditionally regulate gene expression in rat brain; (2) inhibition of ILK expression has no significant effect on cell apoptosis and basal locomotor and stereotypical behaviors, but decreases dendritic density; and (3) microinjection of rAAV-2 causes inflammatory response around the injection track.

We have recently shown in rats that cocaine-induced behavioral sensitization can be reversed by a 5-day treatment with ondansetron given 3.5 h after daily pergolide injections. In this study we further investigated the molecular/neurochemical alterations underlying cocaine sensitization and pergolide/ondansetron-mediated reversal. Results revealed that glutamic acid decarboxylase (GAD(65)/GAD(67)) is higher abundant in the nucleus accumbens (NAc) than that in the caudate and medial prefrontal cortex (mPFC), while GABA(A) receptor alpha2 subunit level in the NAc shell is less abundant than that in the NAc core, mPFC and caudate. Cocaine sensitization led to (1) a decrease in GAD(67) expression, an increase in total protein kinase C (PKC) zeta subtype and phosphorylated PKC zeta/lambda levels in the NAc core; (2) a decrease in GAD(67) and GABA(A) receptor alpha2 subunit expression, and an increase in phosphorylated PKC zeta/lambda levels in the NAc shell; (3) an increase in GAD(67) expression in the caudate. Importantly, pergolide/ondansetron treatment reversed these alterations. These results suggest that reversal of cocaine-induced behavioral sensitization is associated with reversal of region-specific changes in GABA function and PKC activity in the striatum.

The present study investigated whether GABA A receptor α2 subunit and GAD 67 are involved in chronic high dose methamphetamine (METH)-induced sensitization and neurotoxicity. The METH sensitization was established in rats by 7-day pump infusion plus daily injection (25 mg/kg/day) and a subsequent 28-day withdrawal period. Behavioral sensitization was assessed by behavioral ratings after challenge with METH (0.5 mg/kg). The neurotoxicity was evaluated by the expression of glial fibrillary acidic protein (GFAP). Western blot assay showed that METH sensitization decreases GABA A α2 subunit and GAD 67 protein levels in the nucleus accumbens (NAc) core and shell, and conversely, these proteins were increased in the caudate. An upregulation of GFAP expression was observed in the caudate, but not in the NAc core and shell. These data suggest that inhibition of GABA transmission in the NAc is related to METH behavioral sensitization, whereas activation of GABA transmission in the caudate is associated with METH-induced neurotoxicity.

Angiogenesis is essential for solid tumor growth. Although successful antiangiogenic therapies have been demonstrated in animal models, a systematic comparison of the efficacy of different antiangiogenic factors has not been described in the hepatic environment. To address this issue, CT26 murine colon carcinoma cells were transfected with retroviral vectors encoding murine endostatin (mEndostatin), human angiostatin (hAngiostatin), murine-soluble vascular endothelial growth factor receptor-2, (msFlk-1), or murine-soluble Tie2 (msTie2). The transfected cells were then subjected to another round of transfection with a luciferase cDNA-encoding retroviral vector. Expression of these putative antiangiogenic proteins inhibited the proliferation of human umbilical vein endothelial cells in vitro but not tumor cells. To examine effects on tumor growth in vivo, modified cells were delivered via intrasplenic injection into BALB/c mice to induce liver metastases. Tumor burden was measured weekly by bioluminescence. Growth of hepatic metastases in vivo was significantly reduced in mice that were administered cells expressing msTie2 (76% reduction compared with control cells 21 days after intrasplenic inoculation; P < 0.05). Similar results were observed with cells that expressed msFlk-1 and hAngiostatin. However, expression of mEndostatin had no significant effect on the growth of liver metastases compared with control animals. These findings indicate that multiple antiangiogenic pathways are necessary for the growth of hepatic metastases, and each of these pathways is a potential clinically relevant antiangiogenic target for the treatment of this disease.

Phosphatidylinositol 3-kinase (PI3K) is an important signaling molecule involved in cell differentiation, proliferation, survival, and phagocytosis, and may participate in various brain functions. To determine whether it is also involved in cocaine sensitization, we measured the p85{alpha}/p110 PI3K activity in the nuclear accumbens (NAc) shell, NAc core, and prefrontal cortex (PFC) following establishment of cocaine sensitization and its subsequent reversal. Naive rats were rank-ordered and split into either daily cocaine or saline pretreatment group based on their locomotor responses to an acute cocaine injection (7.5 mg/kg, i.p.). These two groups were then injected with cocaine (40 mg/kg, s.c.) or saline for 4 consecutive days followed by 9-day withdrawal. Cocaine sensitization was subsequently reversed by 5 daily injections of the D{sub 1}/D{sub 2} agonist pergolide (0.1 mg/kg, s.c.) in combination with the 5-HT{sub 3} antagonist ondansetron (0.2 mg/kg, s.c., 3.5 h after pergolide injection). After another 9-day withdrawal, behavioral cocaine sensitization and its reversal were confirmed with an acute cocaine challenge (7.5 mg/kg, i.p.), and animals were sacrificed the next day for measurement of p85{alpha}/p110 PI3K activity. Cocaine-sensitized animals exhibited increased PI3K activity in the NAc shell, and this increase was reversed by combined pergolide/ondansetron treatment, which also reversed behavioral sensitization.more » In the NAc core and PFC, cocaine sensitization decreased and increased the PI3K activity, respectively. These changes, in contrast to that in the NAc shell, were not normalized following the reversal of cocaine-sensitization. Interestingly, daily injections of pergolide alone in saline-pretreated animals induced PI3K changes that were similar to the cocaine sensitization-associated changes in the NAc core and PFC but not the NAc shell; furthermore, these changes in saline-pretreated animals were prevented by ondansetron given 3.5 h after pergolide. The present study suggests that selective enhancement of the PI3K activity in the NAc shell may be one of key alterations underlying the long-term cocaine sensitization. To the extent cocaine sensitization is an important factor in human cocaine abuse, pharmacological interventions targeted toward the NAc shell PI3K alteration may be useful in cocaine abuse treatment.« less

Purpose To assess whether administration of recombinant human adenoviral vector, which carries soluble TGFβ1 Type II receptor (TβRII) gene, might reduce the availability of active TGFβ1 and thereby protect the lung from radiation-induced injury. Methods and materials Female Fisher 344 rats were given a single 30 Gy dose of right hemithoracic irradiation 24 h after the injections of control (AdGFP) or treatment (AdexTβRII-Fc) vectors. Different end points were assessed to look for lung tissue damage. Results There was a significant increase in the plasma level of soluble TβRII 24 h and 48 h after injection of treatment vector. In the radiation (RT) + AdexTβRII-Fc group, there was a significant reduction in respiratory rate at 4 weeks after treatment as compared to the RT-alone group. Histologic results revealed a significant reduction in lung damage and decrease in the number and activity of macrophages in the RT + AdexTβRII-Fc group as compared to the RT-alone group. The tissue level of active TGFβ1 was significantly reduced in rats receiving RT + AdexTβRII-Fc treatment. There was also an upregulation of transmembrane TβRII in lung tissue in the RT-alone group as compared to the RT + gene therapy rats. Conclusions This study shows the ability of AdexTβRII-Fc gene therapy to induce an increase in circulating levels of soluble receptors, to reduce the tissue level of active TGFβ1, and consequently to ameliorate acute radiation-induced lung injury.

An efficient approach to the large-scale production of rAAV will significantly facilitate the application of this promising gene delivery vector in human gene therapy applications. In this study, we report a novel approach to rAAV production that is based exclusively on the adenovirus vector, without the need for plasmid transfections and special packaging cell lines. All components required for rAAV production, including the rep and cap genes, and the therapeutic gene(s) are delivered to the widely used 293 packaging cell line by adenovirus vectors. High-titer rAAV vectors (200-600 infectious units/producer cell) were obtained by use of this approach. As adenovirus vectors can be produced to high titers and they can infect cells in suspension efficiently, this approach may be amenable to scaled-up production of rAAV vectors.

Background and purpose Patients with life-threatening illnesses, such as cancer, experience emotional distress. This study was to investigate the molecular and cellular mechanisms of relevant psychological stressor on tumor growth and therapeutic resistance. Materials and Methods Stress was induced in C57BL/6J mice bearing LLC lung tumors by exposure to a conspecific mice receiving inescapable foot shocks. Mice were irradiated at 7 Gy for 3 consecutive days. Behaviors were monitored by open field test (OFT), elevated plus maze (EPM), sucrose preference test (SPT), and learned helplessness (LH) test. Protein expression in tissues and cultured cells were measured by Western blot. Results This study in animals showed that observing a conspecific mouse receiving foot shocks induced depression like behaviors with increased plasma corticosterone and adrenaline levels which increased tumor growth and radioresistance. Stress increased Wnt1, Drosha, and vimentin expression and decreased E-cadherin expression in tumor tissues. The combination of stress and irradiation enhanced radioresistance along with the increase in vimentin expression. The in vitro study showed that a β2-adrenergic receptor (β2-AR) agonist blocked irradiation-induced cell apoptosis and decreased cell viability, while silencing β2-AR expression reduced the protective effects of β2-AR agonist. β2-AR agonist obviously increased Wnt1 and Drosha expression in LLC-1 cells. Conclusion Psychological stress increased tumor growth and enhanced radioresistance associated with the activation of epithelial-mesenchymal transition by stress hormone-stimulated adrenergic receptors.