The role of ionic liquids in the biocatalytic evaluation of bisphenol levels as contaminant: an automatic approach.

An automatic assay was developed that is intended to be a generic tool for evaluation of a horseradish peroxidase activity in different ionic liquids (ILs). Ionic liquids with different characteristics were used and their effects on the enzymatic reaction, were compared with those obtained with conventional organic solvents. In addition, ILs were tested as solvents for the enzyme substrate (bisphenol A (BPA)). ILs were shown to be a good alternative to conventional organic solvents from either the effect on enzymatic activity or the solubilization of bisphenol. Since bisphenol A is an endocrine disruptor frequently used in plastic industries, it was also applied the developed enzymatic methodology for quantification of this compound in real beverage samples. To increase the sensitivity (already increased by the use of an IL) and the selectivity of the methodology, a sample pre-treatment using a molecular recognition solid phase extraction was applied. Finally, the methodology presented detection and quantification limits of 7.73 × 10-4 and 1.29 × 10-3 mmol L-1 and a linear range up to 1.00 mmol L-1, allowing accurate and reliable quantifications of bisphenol in beer and cola drink samples. This work confirmed the potential of a sequential injection analysis (SIA) system as a simple, versatile, robust, and rapid analytical tool for automating enzymatic assays in ILs medium and, at the same time, showed it to be a relevant automatic alternative for routine determinations of bisphenol A in food samples.

Functional activation of dorsal striatum astrocytes improves movement deficits in hemi-parkinsonian mice.

Parkinson's disease (PD) is characterized by the degeneration of dopaminergic nigrostriatal inputs, which causes striatal network dysfunction and leads to pronounced motor deficits. Recent evidence highlights astrocytes as a potential local source of striatal network modulation. However, it remains unknown how dopamine loss affects striatal astrocyte activity and whether astrocyte activity regulates behavioral deficits in PD. We addressed these questions by performing astrocyte-specific calcium recordings and manipulations using in vivo fiber photometry and chemogenetics. We find that locomotion elicits astrocyte calcium activity over a slower timescale than neurons. Unilateral dopamine depletion reduced locomotion-related astrocyte responses. Chemogenetic activation facilitated astrocyte activity, and improved asymmetrical motor deficits and open field exploratory behavior in dopamine lesioned mice. Together, our results establish a novel role for functional striatal astrocyte signaling in modulating motor function in PD and highlight non-neuronal targets for potential PD therapeutics.

A paradigm for ethanol consumption in head-fixed mice during prefrontal cortical two-photon calcium imaging.

The prefrontal cortex (PFC) is a hub for cognitive behaviors and is a key target for neuroadaptations in alcohol use disorders. Recent advances in genetically encoded sensors and functional microscopy allow multimodal in vivo PFC activity recordings at subcellular and cellular scales. While these methods could enable a deeper understanding of the relationship between alcohol and PFC function/dysfunction, they typically require animals to be head-fixed. Here, we present a method in mice for binge-like ethanol consumption during head-fixation. Male and female mice were first acclimated to ethanol by providing home cage access to 20% ethanol (v/v) for 4 or 8 days. After home cage drinking, mice consumed ethanol from a lick spout during head-fixation. We used two-photon calcium imaging during the head-fixed drinking paradigm to record from a large population of PFC neurons (>1000) to explore how acute ethanol affects their activity. Drinking exerted temporally heterogeneous effects on PFC activity at single neuron and population levels. Intoxication modulated the tonic activity of some neurons while others showed phasic responses around ethanol receipt. Population level activity did not show tonic or phasic modulation but tracked ethanol consumption over the minute-timescale. Network level interactions assessed through between-neuron pairwise correlations were largely resilient to intoxication at the population level while neurons with increased tonic activity showed higher synchrony by the end of the drinking period. By establishing a method for binge-like drinking in head-fixed mice, we lay the groundwork for leveraging advanced microscopy technologies to study alcohol-induced neuroadaptations in PFC and other brain circuits. This article is part of the Special Issue on "PFC circuit function in psychiatric disease and relevant models".

PolyQ-Expanded Mutant Huntingtin Forms Inclusion Body Following Transient Cold Shock in a Two-Step Aggregation Mechanism.

Age-dependent formation of insoluble protein aggregates is a hallmark of many neurodegenerative diseases. We are interested in the cell chemistry that drives the aggregation of polyQ-expanded mutant Huntingtin (mHtt) protein into insoluble inclusion bodies (IBs). Using an inducible cell model of Huntington's disease, we show that a transient cold shock (CS) at 4 °C followed by recovery incubation at temperatures of 25-37 °C strongly and rapidly induces the compaction of diffuse polyQ-expanded HuntingtinExon1-enhanced green fluorescent protein chimera protein (mHtt) into round, micron size, cytosolic IBs. This transient CS-induced mHtt IB formation is independent of microtubule integrity or de novo protein synthesis. The addition of millimolar concentrations of sodium chloride accelerates, whereas urea suppresses this transient CS-induced mHtt IB formation. These results suggest that the low temperature of CS constrains the conformation dynamics of the intrinsically disordered mHtt into labile intermediate structures to facilitate de-solvation and hydrophobic interaction for IB formation at the higher recovery temperature. This work, along with our previous observation of the effects of heat shock protein chaperones and osmolytes in driving mHtt IB formation, underscores the primacy of mHtt structuring and rigidification for H-bond-mediated cross-linking in a two-step mechanism of mHtt IB formation in living cells.

A paradigm for ethanol consumption in head-fixed mice during prefrontal cortical two-photon calcium imaging.

The prefrontal cortex (PFC) is a hub for higher-level cognitive behaviors and is a key target for neuroadaptations in alcohol use disorders. Preclinical models of ethanol consumption are instrumental for understanding how acute and repeated drinking affects PFC structure and function. Recent advances in genetically encoded sensors of neuronal activity and neuromodulator release combined with functional microscopy (multiphoton and one-photon widefield imaging) allow multimodal in-vivo PFC recordings at subcellular and cellular scales. While these methods could enable a deeper understanding of the relationship between alcohol and PFC function/dysfunction, they require animals to be head-fixed. Here, we present a method in mice for binge-like ethanol consumption during head-fixation. Male and female mice were first acclimated to ethanol by providing home cage access to 20% ethanol (v/v) for 4 or 8 days. After home cage drinking, mice consumed ethanol from a lick spout during head-fixation. We used two-photon calcium imaging during the head-fixed drinking paradigm to record from a large population of PFC neurons (>1000) to explore how acute ethanol affects their activity. Drinking modulated activity rates in a subset of neurons on slow (minutes) and fast (seconds) time scales but the majority of neurons were unaffected. Moreover, ethanol intake did not significantly affect network level interactions in the PFC as assessed through inter-neuronal pairwise correlations. By establishing a method for binge-like drinking in head-fixed mice, we lay the groundwork for leveraging advanced microscopy technologies to study alcohol-induced neuroadaptations in PFC and other brain circuits.

The druggability of bitter taste receptors for the treatment of neurodegenerative disorders.

The delivery of therapeutic drugs to the brain remains a major pharmacology challenge. A complex system of chemical surveillance to protect the brain from endogenous and exogenous toxicants at brain barriers hinders the uptake of many compounds with significant in vitro and ex vivo therapeutic properties. Despite the advances in the field in recent years, the components of this system are not completely understood. Recently, a large group of chemo-sensing receptors, have been identified in the blood-cerebrospinal fluid barrier. Among these chemo-sensing receptors, bitter taste receptors (TAS2R) hold promise as potential drug targets, as many TAS2R bind compounds with recognized neuroprotective activity (quercetin, resveratrol, among others). Whether activation of TAS2R by their ligands contributes to their diverse biological actions described in other cells and tissues is still debatable. In this review, we discuss the potential role of TAS2R gene family as the mediators of the biological activity of their ligands for the treatment of central nervous system disorders and discuss their potential to counteract drug resistance by improving drug delivery to the brain.

The Sex Bias of Cancer.

In hormone-dependent organs, sex hormones and dysregulated hormone signaling have well-documented roles in cancers of the breast and female reproductive organs including endometrium and ovary, as well as in prostate and testicular cancers in males. Strikingly, epidemiological data highlight significant differences between the sexes in the incidence of various cancers in nonreproductive organs, where the role of sex hormones has been less well studied. In an era when personalized medicine is gaining recognition, understanding the molecular, cellular, and biological differences between men and women is timely for developing more appropriate therapeutic interventions according to gender. We review evidence that sex hormones also shape many of the dysregulated cellular and molecular pathways that lead to cell proliferation and cancer in nonreproductive organs.

Triiodothyronine modulates neuronal plasticity mechanisms to enhance functional outcome after stroke.

The development of new therapeutic approaches for stroke patients requires a detailed understanding of the mechanisms that enhance recovery of lost neurological functions. The efficacy to enhance homeostatic mechanisms during the first weeks after stroke will influence functional outcome. Thyroid hormones (TH) are essential regulators of neuronal plasticity, however, their role in recovery related mechanisms of neuronal plasticity after stroke remains unknown. This study addresses important findings of 3,5,3'-triiodo-L-thyronine (T3) in the regulation of homeostatic mechanisms that adjust excitability - inhibition ratio in the post-ischemic brain. This is valid during the first 2 weeks after experimental stroke induced by photothrombosis (PT) and in cultured neurons subjected to an in vitro model of acute cerebral ischemia. In the human post-stroke brain, we assessed the expression pattern of TH receptors (TR) protein levels, important for mediating T3 actions.Our results show that T3 modulates several plasticity mechanisms that may operate on different temporal and spatial scales as compensatory mechanisms to assure appropriate synaptic neurotransmission. We have shown in vivo that long-term administration of T3 after PT significantly (1) enhances lost sensorimotor function; (2) increases levels of synaptotagmin 1&2 and levels of the post-synaptic GluR2 subunit in AMPA receptors in the peri-infarct area; (3) increases dendritic spine density in the peri-infarct and contralateral region and (4) decreases tonic GABAergic signaling in the peri-infarct area by a reduced number of parvalbumin+ / c-fos+ neurons and glutamic acid decarboxylase 65/67 levels. In addition, we have shown that T3 modulates in vitro neuron membrane properties with the balance of inward glutamate ligand-gated channels currents and decreases synaptotagmin levels in conditions of deprived oxygen and glucose. Interestingly, we found increased levels of TRß1 in the infarct core of post-mortem human stroke patients, which mediate T3 actions. Summarizing, our data identify T3 as a potential key therapeutic agent to enhance recovery of lost neurological functions after ischemic stroke.