A quantitative trait variant in Gabra2 underlies increased methamphetamine stimulant sensitivity

Psychostimulant (methamphetamine, cocaine) use disorders have a genetic component that remains mostly unknown. We conducted genome-wide quantitative trait locus (QTL) analysis of methamphetamine stimulant sensitivity. To facilitate gene identification, we employed a Reduced Complexity Cross between closely related C57BL/6 mouse substrains and examined maximum speed and distance traveled over 30 min following methamphetamine (2 mg/kg, i.p.). For maximum methamphetamine-induced speed following the second and third administration, we identified a single genome-wide significant QTL on chromosome 11 that peaked near the Cyfip2 locus (LOD = 3.5, 4.2; peak = 21 cM [36 Mb]). For methamphetamine-induced distance traveled following the first and second administration, we identified a genome-wide significant QTL on chromosome 5 that peaked near a functional intronic indel in Gabra2 coding for the alpha-2 subunit of the GABA-A receptor (LOD = 3.6–5.2; peak = 34–35 cM [66–67 Mb]). Striatal cis-expression QTL mapping corroborated Gabra2 as a functional candidate gene underlying methamphetamine-induced distance traveled. CRISPR/Cas9-mediated correction of the mutant intronic deletion on the C57BL/6J background to the wild-type C57BL/6NJ allele was sufficient to reduce methamphetamine-induced locomotor activity toward the wild-type C57BL/6NJ-like level, thus validating the quantitative trait variant (QTV). These studies show the power and efficiency of Reduced Complexity Crosses in identifying causal variants underlying complex traits. Functionally restoring Gabra2 expression decreased methamphetamine stimulant sensitivity and supports preclinical and human genetic studies implicating the GABA-A receptor in psychostimulant addiction-relevant traits. Importantly, our findings have major implications for studying psychostimulants in the C57BL/6J strain—the gold standard strain in biomedical research.     

Toxicity of rhizomes of the invasive Hedychium coronarium (Zingiberaceae) on aquatic species

The production and release of chemical compounds by invasive plants can affect competitors and native species overall, destabilizing ecological interactions and harming ecosystem functioning. Hedychium coronarium is an invasive macrophyte common on Brazilian riparian areas that produces a wide variety of allelochemicals, but little is known about their effect on aquatic species. Here, we identified the major chemical compounds of the aqueous extract of H. coronarium rhizomes and assessed its toxicity, evaluating the growth inhibition of one alga (Raphidocelis subcapitata) and one macrophyte (Lemna minor), and the lethality of cladoceran (Ceriodaphnia silvestrii and Daphnia similis) and Chironomidae larvae (Chironomus sancticaroli). The majoritarian compounds of H. coronarium rhizomes were Coronarin D and Coronarin D Ethyl Ether. The aqueous extract was toxic for all tested species. We observed growth inhibition in R. subcapitata, as well as reduction in biomass in L. minor. Chironomus sancticaroli and cladoceran were the most sensible species. The aqueous extract of H. coronarium rhizomes was toxic on tested conditions, suggesting that the rhizome compounds may interfere on aquatic organisms and in the dynamic of trophic webs of aquatic ecosystems on invaded areas.

     

Uncertainty in research about key invasion characteristics limits the evaluation of exotic perennial grasses in natural systems in New South Wales,Australia

Exotic perennial grasses (EPGs) pose a significant risk to native communities globally. With over 2,200 species in Australia, understanding which characteristics enable high threat invasions, and comparing between functionally similar EPGs, can help prioritise species management. We developed a framework of risk and used the literature to rank 21 EPGs considered a threat to plant communities in New South Wales, while also evaluating the reliability of information currently available. Characteristics were scored within five broad categories that distinguish invasiveness: Arrival, Establishment, Persistence, Impact and Distribution. These included aspects of reproductive biology, competitive ability and environmental tolerance. The risk assessment was effective in assessing key characteristics of invasion. EPGs with an economic benefit (trade‐off species) were more likely to have reliable research and frequently ranked as high‐risk invaders in natural habitats due to the overlap of characteristics important in invasion with those considered important in agriculture. Lack of formal scientific research hindered assessment for some species, and some traits had been poorly assessed in the literature. High uncertainty was associated with key characteristics for Establishment, Persistence and Impact. Uncertainty in key characteristics revealed a need for improved integration of less formal research validated by more formal scientific research. This may lead to more informed decisions in the management of EPGs in native habitats and assist in early control of EPGs not yet assessed.     

Flavonoids: A complementary approach to conventional therapy of COVID-19?

Phytochemistry Reviews - COVID-19, the highly contagious novel disease caused by SARS-CoV-2, has become a major international concern as it has spread quickly all over the globe. However,...     

Investigation of the Molecular Nature of Low-molecular-mass Cobalt(II) Ions in Isolated Osteoarthritic Knee-joint Synovial Fluid

High field ¹H NMR spectroscopy demonstrated that addition of Co(II) ions to osteoarthritic knee-joint synovial fluid (SF) resulted in its complexation by a range of biomolecules, the relative efficacies of these complexants/chelators being citrate ? histidine ～ threonine?glycine ～ glutamate ～ glutamine ～ phenylalanine ～ tyrosine > formate > lactate?alanine > valine > acetate > pyruvate > creatinine, this order reflecting the ability of these ligands to compete for the available Co(II) in terms of (1) thermodynamic equilibrium constants for the formation of their complexes and (2) their SF concentrations. Since many of these SF Co(II) complexants (e.g. histidinate) serve as powerful ^?OH scavengers, the results acquired indicate that any of this radical generated from the Co(II) source in such complexes via Fenton or pseudo-Fenton reaction systems will be “site-specifically” scavenged. The significance of these observations with regard to cobalt toxicity and the in vivo corrosion of cobalt-containing metal alloy joint prostheses (e.g. CoCr alloys) is discussed.     

Synergistic antifungal activity of statin–azole associations as witnessed by Saccharomyces cerevisiae- and Candida utilis-bioassays and ergosterol quantification

BackgroundFrequent opportunist fungal infections and the resistance to available antifungal drugs promoted the development of new alternatives for treatment, like antifungal drug combinations.AimsThis work aimed to detect the antifungal synergism between statins and azoles by means of an agar-well diffusion bioassay with Saccharomyces cerevisiae ATCC 32051 and Candida utilis Pr_1–2 as test strains.MethodsSynergistic antifungal effects were tested by simultaneously adding a sub inhibitory concentration (SIC) of statin (atorvastatin, lovastatin, pravastatin, rosuvastatin or simvastatin) plus a minimal inhibitory concentration (MIC) of azole (clotrimazole, fluconazole, itraconazole, ketoconazole or miconazole) to yeast-embedded YNB agar plates, and a positive result corresponded to a yeast growth inhibition halo higher than that produced by the MIC of the azole alone. Yeast cell ergosterol quantification by RP-HPLC was used to confirm statin–azole synergism, and ergosterol rescue bioassays were performed for evaluating statin-induced ergosterol synthesis blockage.ResultsGrowth inhibition was significantly increased when clotrimazole, fluconazole, itraconazole, ketoconazole and miconazole were combined with atorvastatin, lovastatin, rosuvastatin and simvastatin. Highest growth inhibition increments were observed on S. cerevisiae (77.5%) and C. utilis (43.2%) with a SIC of simvastatin plus a MIC of miconazole, i.e. 4 + 2.4 μg/ml or 20 + 4.8 μg/ml, respectively. Pravastatin showed almost no significant effects (0–7.6% inhibition increase). Highest interaction ratios between antifungal agents corresponded to simvastatin–miconazole combinations and were indicative of synergism. Synergism was also confirmed by the increased reduction in cellular ergosterol levels (S. cerevisiae, 40% and C. utilis, 22%). Statin-induced ergosterol synthesis blockage was corroborated by means of ergosterol rescue bioassays, pravastatin being the most easily abolished inhibition whilst rosuvastatin being the most ergosterol-refractory.ConclusionsSelected statin–azole combinations might be viable alternatives for the therapeutic management of mycosis at lower administration doses or with a higher efficiency.     

Epithelial cell adhesion molecule (EpCAM) is associated with prostate cancer metastasis and chemo/radioresistance via the PI3K/Akt/mTOR signaling pathway

Prostate cancer (CaP) is the second leading malignancy in men. The role of epithelial cell adhesion molecule (EpCAM), also known as CD326, in CaP progression and therapeutic resistance is still uncertain. Here, we aimed to investigate the roles of EpCAM in CaP metastasis and chemo/radioresistance. Expression of EpCAM in CaP cell lines and human CaP tissues was assessed using immunofluorescence and immunohistochemistry, respectively. EpCAM was knocked down (KD) in PC-3, DU145 and LNCaP-C4-2B cells using small interfering RNA (siRNA), and KD results were confirmed by confocal microscope, Western blotting and quantitative real time polymerase chain reaction (qRT-PCR). Cell growth was evaluated by proliferation and colony formation assays. The invasive potential was assessed using a matrigel chamber assay. Tumorigenesis potential was measured by a sphere formation assay. Chemo-/radiosensitivity were measured using a colony formation assay. Over-expression of EpCAM was found in primary CaP tissues and lymph node metastases including cancer cells and surrounding stromal cells. KD of EpCAM suppressed CaP proliferation and invasive ability, reduced sphere formation, enhanced chemo-/radiosensitivity, and down-regulated E-cadherin, p-Akt, p-mTOR, p-4EBP1 and p-S6K expression in CaP cells. Our findings suggest that EpCAM plays an important role in CaP proliferation, invasion, metastasis and chemo-/radioresistance associated with the activation of the PI3K/Akt/mTOR signaling pathway and is a novel therapeutic target to sensitize CaP cells to chemo-/radiotherapy.     

Lysophosphatidic acid,human osteoblast formation,maturation and the role of 1α,25-Dihydroxyvitamin D3 (calcitriol)

The simplest signalling lipid Lysophosphatidic acid (LPA) elicits pleiotropic actions upon most mammalian cell types. Although LPA has an established role in many biological processes, particularly wound healing and cancer, the function of LPA for human osteoblast (hOB) biology is still unravelling. Early studies, identified in this review, gave a reliable indication that LPA, via binding to one of several transmembrane receptors, stimulated multiple intracellular signalling networks coupled to changes in cell growth, fibronectin binding, maturation and survival. The majority of studies exploring the actions of LPA on hOB responses have done so using the lipid in isolation. Our own research has focussed on the co-operation of LPA with the active vitamin D3 metabolite, 1α25,dihydroxycholecalciferol (calcitriol), in light of a serendipitous discovery that calcitriol, in a serum-free culture setting, was unable to promote hOB maturation. We subsequently learnt that the serum-borne factor co-operating with calcitriol to enhance hOB differentiation was LPA bound to the albumin fraction of whole serum. Recent studies from our laboratory have identified that LPA and calcitriol are a potent pairing for securing hOB formation from their stem cell progeny. Greater understanding of the ability of LPA to influence, for example, hOB growth, maturation and survival could be advantageous in developing novel strategies aimed at improving skeletal tissue repair and regeneration. Herein this review provides an insight into the diversity of studies exploring the actions of a small lipid on a major cell type key to bone tissue health and homeostasis. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.