Microfluidic-derived docosahexaenoic acid liposomes for glioblastoma therapy

Glioblastoma (GBM) is the most prevalent malignant primary brain tumor and currently lacks an effective treatment. In this study, we utilized a microfluidic system to synthesize docosahexaenoic acid (DHA) liposomes for GBM therapy. DHA is an omega-3 (ω3) polyunsaturated fatty acid commonly found in human dietary consumption that has demonstrated potential in mitigating cancer development. The microfluidic device employed allowed for precise fine-tuning of the physicochemical properties of liposomes by adjusting the flow rate ratios, flow rates, and lipid concentrations. Three distinct-sized liposomes, ranging from 80 nm and 130 nm, were successfully internalized by GBM cells, and demonstrated the ability to reduce the viability of these cells. Furthermore, DHA liposomes proved significantly more efficient in triggering apoptotic pathways, through caspase-3-dependent mechanisms, in comparison to free DHA. Thus, the nanomedicine platform established in this study presents new opportunities in the development of liposome formulations incorporating ω3 fatty acids for cancer therapy.

Differential regulation of STP, LTP and LTD by structurally diverse NMDA receptor subunit-specific positive allosteric modulators

Different types of memory are thought to rely on different types of synaptic plasticity, many of which depend on the activation of the N-Methyl-D Aspartate (NMDA) subtype of glutamate receptors. Accordingly, there is considerable interest in the possibility of using positive allosteric modulators (PAMs) of NMDA receptors (NMDARs) as cognitive enhancers. Here we firstly review the evidence that NMDA receptor-dependent forms of synaptic plasticity: short-term potentiation (STP), long-term potentiation (LTP) and long-term depression (LTD) can be pharmacologically differentiated by using NMDAR ligands. These observations suggest that PAMs of NMDAR function, depending on their subtype selectivity, might differentially regulate STP, LTP and LTD. To test this hypothesis, we secondly performed experiments in rodent hippocampal slices with UBP714 (a GluN2A/2B preferring PAM), CIQ (a GluN2C/D selective PAM) and UBP709 (a pan-PAM that potentiates all GluN2 subunits). We report here, for the first time, that: (i) UBP714 potentiates sub-maximal LTP and reduces LTD; (ii) CIQ potentiates STP without affecting LTP; (iii) UBP709 enhances LTD and decreases LTP. We conclude that PAMs can differentially regulate distinct forms of NMDAR-dependent synaptic plasticity due to their subtype selectivity.

This article is part of the Neuropharmacology Special Issue on ‘Glutamate Receptors – NMDA receptors’.

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NMDAR-dependent STP, LTP and LTD can be dissociated pharmacologically

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GluN2A/2B PAM UBP714 potentiates LTP and reduces LTD

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GluN2C/D PAM CIQ potentiates STP without affecting LTP

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NMDAR pan-PAM UBP709 potentiates LTD and reduces LTP

Diagnostic parameters and reliability of four rapid immunochromatographic tests for dengue 4

BACKGROUND

Although performance of rapid immunochromatographic tests (RITs) for dengue virus (DENV) serotypes 1, 2 and 3 is relatively settled, evidence on accuracy of RITs for DENV-4 are based on studies with small sample sizes and with discrepant results.

OBJECTIVES

To assess accuracy and inter-observer agreement of RITs targeting dengue nonstructural protein-1 (NS1) antigen - Dengue NS1-Bioeasy™, Dengue NS1 Ag Strip-Bio-Rad™, IVB Dengue Ag NS1-Orangelife™ and Dengue NS1-K130-Bioclin™ in DENV-4 samples.

METHODS

Study sample (n = 324) included adults presenting at an emergency unit in Rio de Janeiro, Brazil, with fever of ≤72 h and two or more dengue symptoms. A serum sample from each patient was tested by each RIT. A positive reverse-transcription polymerase chain reaction was considered as the reference standard for dengue diagnosis. The diagnostic parameters analyzed for each RIT were sensitivity, specificity, positive and negative predictive values, and likelihood ratios. Each RIT was read by homogeneous (two junior nurses) or heterogeneous (one junior nurse and one senior biologist) pairs. Agreement was estimated by simple kappa with 95% confidence interval, positive (Ppos) and negative (Pneg) proportion concordance and prevalence and bias adjusted kappa, rated from poor (k < 0.0) to almost perfect (0.8 < k < 1.0), and perfect (k = 1).

RESULTS

NS1 RITs for DENV-4 diagnosis showed high specificity (95.9%-99.4%), but low sensitivity (14.7%-45.4%). Bioeasy™ had the best performance, with a positive likelihood ratio of 26.0 (95% CI: 8.4;81.0). Inter-observer agreement was almost perfect for all evaluated RITs. Mismatches in confirmed dengue were more common for the Bioclin™ (Ppos 88.3-90.0 %) and Orangelife™ (Ppos 91.7-94.1 %) tests.

CONCLUSIONS

For DENV-4, the tested RITs had high specificity, but lower sensitivity compared to published results for other serotypes. They should not be used for screening purposes. Different brands may have very different performances. This should be considered upon deciding of using RITs in DENV-4 outbreaks.

Mechanisms of initiation and reversal of drug-seeking behavior induced by prenatal exposure to glucocorticoids

Stress and exposure to glucocorticoids (GC) during early life render individuals vulnerable to brain disorders by inducing structural and chemical alterations in specific neural substrates. Here we show that adult rats that had been exposed to in utero GCs (iuGC) display increased preference for opiates and ethanol, and are more responsive to the psychostimulatory actions of morphine. These animals presented prominent changes in the nucleus accumbens (NAcc), a key component of the mesolimbic reward circuitry; specifically, cell numbers and dopamine (DA) levels were significantly reduced, whereas DA receptor 2 (Drd2) mRNA expression levels were markedly upregulated in the NAcc. Interestingly, repeated morphine exposure significantly downregulated Drd2 expression in iuGC-exposed animals, in parallel with increased DNA methylation of the Drd2 gene. Administration of a therapeutic dose of L-dopa reverted the hypodopaminergic state in the NAcc of iuGC animals, normalized Drd2 expression and prevented morphine-induced hypermethylation of the Drd2 promoter. In addition, L-dopa treatment promoted dendritic and synaptic plasticity in the NAcc and, importantly, reversed drug-seeking behavior. These results reveal a new mechanism through which drug-seeking behaviors may emerge and suggest that a brief and simple pharmacological intervention can restrain these behaviors in vulnerable individuals.