Maria Grazia Ennas

Background and Purpose: Spice/K2 herbal mixtures, containing synthetic cannabinoids such as JWH‐018, have been marketed as marijuana surrogates since 2004. JWH‐018 has cannabinoid CB₁ receptor‐dependent reinforcing properties and acutely increases dopaminergic transmission selectively in the NAc shell. Here, we tested the hypothesis that repeated administration of JWH‐018 (i) modulates behaviour, (ii) affects dopaminergic transmission and its responsiveness to motivational stimuli, and (iii) is associated with a neuroinflammatory phenotype.Experimental Approach: Rats were administered with JWH‐018 once a day for 14 consecutive days. We then performed behavioural, electrophysiological, and neurochemical evaluation at multiple time points after drug discontinuation.Key Results: Repeated JWH‐018 exposure (i) induced anxious and aversive behaviours, transitory attentional deficits, and withdrawal signs; (ii) decreased spontaneous activity and number of dopamine neurons in the VTA; and (iii) reduced stimulation of dopaminergic transmission in the NAc shell while potentiating that in the NAc core, in response to acute JWH‐018 challenge. Moreover, (iv) we observed a decreased dopamine sensitivity in the NAc shell and core, but not in the mPFC, to a first chocolate exposure; conversely, after a second exposure, dialysate dopamine fully increased in the NAc shell and core but not in the mPFC. Finally, selected dopamine brain areas showed (v) astrogliosis (mPFC, NAc shell and core, VTA), microgliosis (NAc shell and core), and downregulation of CB₁ receptors (mPFC, NAc shell and core).Conclusion and Implications: Repeated exposure to JWH‐018 may provide a useful model to clarify the detrimental effects of recurring use of Spice/K2 drugs.

Background Exposure to high molecular weight agents, such as those associated with organic dust, has shown an inverse association with lymphoma risk. In this paper, we used the data base of the multicentre European case-control study EPILYMPH to explore risk of lymphoma subtypes associated with occupational exposure to six different types of organic dust. Methods During 1998–2004, a case-control study on the aetiology of lymphoma was conducted in six European countries. Overall, assessment of exposure to organic dust was completed in 1941 cases and 1992 controls. Risk of the major lymphoma subtypes associated with exposure to any organic dust, flour dust, hardwood, softwood, leather and natural and artificial textile fibres was calculated with unconditional logistic regression analysis, adjusting by age, gender, education and study centre. Results Risk of B-cell lymphoma associated with exposure to any organic dust was inverse (OR = 0.6, 95% CI: 0.3–1.0), with a significant inverse trend by duration and intensity of exposure. The inverse association was strongest for exposure to flour and wood dust, independent on whether hardwood or softwood. The inverse association was likewise observed ifor diffuse large B cell lymphoma, follicular lymphoma, and chronic lymphocytic leukaemia. Conclusions Our results appear to confirm an inverse association of risk of the major lymphoma subtypes with exposure to organic dust, and aprticularly with flour dust and wood dust.

Genes encoding for arylamine N‐acetyltransferase 1 and 2 (NAT1 and NAT2) have been investigated with alternate findings in relation to risk of non‐Hodgkin lymphoma (NHL). We tested functional haplotype‐based NAT1 and NAT2 gene polymorphisms in relation to risk of lymphoma overall and its major B cell subtypes, diffuse large B cell lymphoma (DLBCL), follicular lymphoma (FL) and chronic lymphocytic leukaemia (CLL). We used allele specific primers and multiplex PCR to detect NAT1 and NAT2 haplotypes in 248 patients with incident lymphoma and 208 population controls. We inferred the NAT1 rapid and slow acetylator and the NAT2 rapid, intermediate or slow acetylator phenotype, based on published functional data on the respective genotypes. Odds ratios and 95% confidence intervals (95% CIs) for lymphoma, B‐NHL, DLBCL, FL, CLL, and other B‐NHL combined associated with the inferred rapid NAT1 acetylator and with the intermediate and slow NAT2 acetylator phenotypes were estimated with unconditional and polytomous logistic regression analysis, adjusting for age, gender and education. NAT1 rapid acetylators showed a 2.8‐fold excess risk (95% CI 1.5–5.2) for lymphoma (all subtypes combined). Risk was highest for CLL and FL, with significant heterogeneity detected across subtypes. Risk also increased with decreasing NAT2 acetylating capacity with no heterogeneity detected across B cell lymphoma subtypes. Risks did not vary by gender. Although poor statistical power was a major limitation in our study, larger studies and pooled analyses are warranted to test whether NAT1 and NAT2 gene polymorphisms might modulate risk of specific lymphoma subtypes through the varying metabolic activity of their products. Copyright © 2015 John Wiley & Sons, Ltd.

Methamphetamine (METH) is a potent psychostimulant with neurotoxic properties. Heavy use increases the activation of neuronal nitric oxide synthase (nNOS), production of peroxynitrites, microglia stimulation, and induces hyperthermia and anorectic effects. Most METH recreational users also consume cannabis. Preclinical studies have shown that natural (Δ9-tetrahydrocannabinol, Δ9-THC) and synthetic cannabinoid CB1 and CB2 receptor agonists exert neuroprotective effects on different models of cerebral damage. Here, we investigated the neuroprotective effect of Δ9-THC on METH-induced neurotoxicity by examining its ability to reduce astrocyte activation and nNOS overexpression in selected brain areas. Rats exposed to a METH neurotoxic regimen (4×10 mg/kg, 2 hours apart) were pre- or post-treated with Δ9-THC (1 or 3 mg/kg) and sacrificed 3 days after the last METH administration. Semi-quantitative immunohistochemistry was performed using antibodies against nNOS and Glial Fibrillary Acidic Protein (GFAP). Results showed that, as compared to corresponding controls (i) METH-induced nNOS overexpression in the caudate-putamen (CPu) was significantly attenuated by pre- and post-treatment with both doses of Δ9-THC (−19% and −28% for 1 mg/kg pre- and post-treated animals; −25% and −21% for 3 mg/kg pre- and post-treated animals); (ii) METH-induced GFAP-immunoreactivity (IR) was significantly reduced in the CPu by post-treatment with 1 mg/kg Δ9-THC1 (−50%) and by pre-treatment with 3 mg/kg Δ9-THC (−53%); (iii) METH-induced GFAP-IR was significantly decreased in the prefrontal cortex (PFC) by pre- and post-treatment with both doses of Δ9-THC (−34% and −47% for 1 mg/kg pre- and post-treated animals; −37% and −29% for 3 mg/kg pre- and post-treated animals). The cannabinoid CB1 receptor antagonist SR141716A attenuated METH-induced nNOS overexpression in the CPu, but failed to counteract the Δ9-THC-mediated reduction of METH-induced GFAP-IR both in the PFC and CPu. Our results indicate that Δ9-THC reduces METH-induced brain damage via inhibition of nNOS expression and astrocyte activation through CB1-dependent and independent mechanisms, respectively.

Susan Slager and colleagues report a meta-analysis of genome-wide association studies for chronic lymphocytic leukemia (CLL). They identify nine loci newly associated with CLL. Genome-wide association studies (GWAS) have previously identified 13 loci associated with risk of chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL). To identify additional CLL susceptibility loci, we conducted the largest meta-analysis for CLL thus far, including four GWAS with a total of 3,100 individuals with CLL (cases) and 7,667 controls. In the meta-analysis, we identified ten independent associated SNPs in nine new loci at 10q23.31 (ACTA2 or FAS (ACTA2/FAS), P = 1.22 × 10−14), 18q21.33 (BCL2, P = 7.76 × 10−11), 11p15.5 (C11orf21, P = 2.15 × 10−10), 4q25 (LEF1, P = 4.24 × 10−10), 2q33.1 (CASP10 or CASP8 (CASP10/CASP8), P = 2.50 × 10−9), 9p21.3 (CDKN2B-AS1, P = 1.27 × 10−8), 18q21.32 (PMAIP1, P = 2.51 × 10−8), 15q15.1 (BMF, P = 2.71 × 10−10) and 2p22.2 (QPCT, P = 1.68 × 10−8), as well as an independent signal at an established locus (2q13, ACOXL, P = 2.08 × 10−18). We also found evidence for two additional promising loci below genome-wide significance at 8q22.3 (ODF1, P = 5.40 × 10−8) and 5p15.33 (TERT, P = 1.92 × 10−7). Although further studies are required, the proximity of several of these loci to genes involved in apoptosis suggests a plausible underlying biological mechanism.

Ventral tegmental area dopamine neurons control reward-driven learning, and their dysregulation can lead to psychiatric disorders. Tonic and phasic activity of these dopaminergic neurons depends on cholinergic tone and activation of nicotinic acetylcholine receptors (nAChRs), particularly those containing the β2 subunit (β2*-nAChRs). Nuclear peroxisome proliferator-activated receptors type-α (PPARα) tonically regulate β2*-nAChRs and thereby control dopamine neuron firing activity. However, it is unknown how and when PPARα endogenous ligands are synthesized by dopamine cells. Usingex vivoandin vivoelectrophysiological techniques combined with biochemical and behavioral analysis, we show that activation of α7-nAChRs increases in the rat VTA both the tyrosine phosphorylation of the β2 subunit of nAChRs and the levels of two PPARα endogenous ligands in a Ca²⁺-dependent manner. Accordingly,in vivoproduction of endogenous PPARα ligands, triggered by α7-nAChR activation, blocks in rats nicotine-induced increased firing activity of dopamine neurons and displays antidepressant-like properties. These data demonstrate that endogenous PPARα ligands are effectors of α7-nAChRs and that their neuromodulatory properties depend on phosphorylation of β2*-nAChRs on VTA dopamine cells. This reveals an autoinhibitory mechanism aimed at reducing dopamine cell overexcitation engaged during hypercholinergic drive. Our results unveil important physiological functions of nAChR/PPARα signaling in dopamine neurons and how behavioral output can change after modifications of this signaling pathway. Overall, the present study suggests PPARα as new therapeutic targets for disorders associated with unbalanced dopamine–acetylcholine systems.