Brain Cholesterol Biosynthetic Pathway Is Altered in a Preclinical Model of Fragile X Syndrome

Fragile X Syndrome (FXS) is the most frequent form of inherited X-linked pathology, associated with an intellectual and developmental disability, and currently considered the first monogenic cause of autism spectrum disorder (ASD). Low levels of total cholesterol reported in the serum of FXS patients, and evidence that FMRP targets a subset of mRNAs encoding proteins of lipid synthesis and transport suggests that the cholesterol metabolism impairments could be involved in FXS. Thus, the aim of the presented work was to investigate the modulations of the cholesterol biosynthetic pathway and its end-products in a recently developed Fmr1-Δexon 8 rat model of FXS. Here, we show that this experimental model mimics what is found in FXS patients, exhibiting a lower serum cholesterol content, accompanied by a reduction in food intake and body weight compared to WT animals. Moreover, alterations of proteins committed to cholesterol synthesis and uptake have been observed in the amygdala, prefrontal cortex and nucleus accumbens. Interestingly, the end-products show a brain region-dependent modulation in Fmr1-Δexon 8 rats. Overall, our results demonstrate that the cholesterol biosynthetic pathway is altered in some brain regions of this preclinical model of FXS. This finding has relevance for future studies to delve deeper into the involvement of this metabolic process in FXS, and thus its possible role as a therapeutic target.     

The Protective Effect of a Unique Mix of Polyphenols and Micronutrients against Neurodegeneration Induced by an In Vitro Model of Parkinson’s Disease

Parkinson’s disease (PD) is second-most common disabling neurological disorder worldwide, and unfortunately, there is not yet a definitive way to prevent it. Polyphenols have been widely shown protective efficacy against various PD symptoms. However, data on their effect on physio-pathological mechanisms underlying this disease are still lacking. In the present work, we evaluated the activity of a mixture of polyphenols and micronutrients, named A5⁺, in the murine neuroblastoma cell line N1E115 treated with 6-Hydroxydopamine (6-OHDA), an established neurotoxic stimulus used to induce an in vitro PD model. We demonstrate that a pretreatment of these cells with A5⁺ causes significant reduction of inflammation, resulting in a decrease in pro-inflammatory cytokines (IFN-γ, IL-6, TNF-α, and CXCL1), a reduction in ROS production and activation of extracellular signal-regulated kinases (ERK)1/2, and a decrease in apoptotic mechanisms with the related increase in cell viability. Intriguingly, A5⁺ treatment promoted cellular differentiation into dopaminergic neurons, as evident by the enhancement in the expression of tyrosine hydroxylase, a well-established dopaminergic neuronal marker. Overall, these results demonstrate the synergic and innovative efficacy of A5⁺ mixture against PD cellular pathological processes, although further studies are needed to clarify the mechanisms underlying its beneficial effect.     

Conjugation with Phospholipids as a Modification Increasing Anticancer Activity of Phenolic Acids in Metastatic Melanoma—In Vitro and In Silico Studies

Phenolic acids possess many beneficial biological activities, including antioxidant and anti-inflammatory properties. Unfortunately, their low bioavailability restricts their potential medical uses, as it limits the concentration of phenolic acids achievable in the organism. The conjugation with phospholipids constitutes one of the most effective strategies to enhance compounds bioavailability in biological systems. In the present study, the conjugates of anisic (ANISA) and veratric acid (VA) with phosphatidylcholine (PC) were investigated. Since both ANISA and VA are inhibitors of tyrosinase, a melanocyte enzyme, the expression of which increases during tumorigenesis, anticancer potential of the conjugates was tested in several metastatic melanoma cell lines. The conjugates proved to be antiproliferative, apoptosis-inducing and cell-cycle-affecting agents, selective for cancerous cells and not affecting normal fibroblasts. The conjugates substituted by ANISA and VA, respectively, at both the sn-1 and sn-2 positions of PC, appeared the most promising, since they were effective against the vast majority of metastatic melanoma cell lines. Additionally, the conjugation of phenolic acids to PC increased their antioxidant activity. Molecular modeling was employed for the first time to estimate the features of the investigated conjugates relevant to their anticancer properties and membrane permeation. Again, the conjugates substituted by phenolic acid at both the sn-1 and sn-2 positions of PC seemed to be presumably most bioavailable.     

In Vitro Assays to Identify Metabolism-Disrupting Chemicals with Diabetogenic Activity in a Human Pancreatic β-Cell Model

There is a need to develop identification tests for Metabolism Disrupting Chemicals (MDCs) with diabetogenic activity. Here we used the human EndoC-βH1 β-cell line, the rat β-cell line INS-1E and dispersed mouse islet cells to assess the effects of endocrine disruptors on cell viability and glucose-stimulated insulin secretion (GSIS). We tested six chemicals at concentrations within human exposure (from 0.1 pM to 1 µM). Bisphenol-A (BPA) and tributyltin (TBT) were used as controls while four other chemicals, namely perfluorooctanoic acid (PFOA), triphenylphosphate (TPP), triclosan (TCS) and dichlorodiphenyldichloroethylene (DDE), were used as “unknowns”. Regarding cell viability, BPA and TBT increased cell death as previously observed. Their mode of action involved the activation of estrogen receptors and PPARγ, respectively. ROS production was a consistent key event in BPA-and TBT-treated cells. None of the other MDCs tested modified viability or ROS production. Concerning GSIS, TBT increased insulin secretion while BPA produced no effects. PFOA decreased GSIS, suggesting that this chemical could be a “new” diabetogenic agent. Our results indicate that the EndoC-βH1 cell line is a suitable human β-cell model for testing diabetogenic MDCs. Optimization of the test methods proposed here could be incorporated into a set of protocols for the identification of MDCs.     

Pioglitazone Attenuates the Effects of Peripheral Inflammation in a Human In Vitro Blood–Brain Barrier Model

Biological mediators secreted during peripheral chronic inflammation reach the bloodstream and may damage the blood–brain barrier (BBB), triggering central nervous system (CNS) disorders. Full-fledged human BBB models are efficient tools to investigate pharmacological pathways and mechanisms of injury at the BBB. We here employed a human in vitro BBB model to investigate the effects of either plasma from inflammatory bowel disease (IBD) patients or tumor necrosis factor α (TNFα), a cytokine commonly released in periphery during IBD, and the anti-inflammatory role of pioglitazone, a peroxisome proliferator-activated receptor γ agonist (PPARγ). The BBB model was treated with either 10% plasma from healthy and IBD donors or 5 ng/mL TNFα, following treatment with 10 µM pioglitazone. Patient plasma did not alter BBB parameters, but TNFα levels in plasma from all donors were associated with varying expression of claudin-5, claudin-3 and ICAM-1. TNFα treatment increased BBB permeability, claudin-5 disarrangement, VCAM-1 and ICAM-1 expression, MCP1 secretion and monocyte transmigration. These effects were attenuated by pioglitazone. Plasma from IBD patients, which evoked higher BBB permeability, also increased ICAM-1 expression, this effect being reversed by pioglitazone. Our findings evidence how pioglitazone controls periphery-elicited BBB inflammation and supports its repurposing for prevention/treating of such inflammatory conditions.     

The Search for New Anticonvulsants in a Group of (2,5-Dioxopyrrolidin-1-yl)(phenyl)Acetamides with Hybrid Structure—Synthesis and In Vivo/In Vitro Studies

Epilepsy belongs to the most common and debilitating neurological disorders with multifactorial pathophysiology and a high level of drug resistance. Therefore, with the aim of searching for new, more effective, and/or safer therapeutics, we discovered a focused series of original hybrid pyrrolidine-2,5-dione derivatives with potent anticonvulsant properties. We applied an optimized coupling reaction yielding several hybrid compounds that showed broad-spectrum activity in widely accepted animal seizure models, namely, the maximal electroshock (MES) test and the psychomotor 6 Hz (32 mA) seizure model in mice. The most potent anticonvulsant activity and favorable safety profile was demonstrated for compound 30 (median effective dose (ED₅₀) MES = 45.6 mg/kg, ED₅₀ 6 Hz (32 mA) = 39.5 mg/kg, median toxic dose (TD₅₀) (rotarod test) = 162.4 mg/kg). Anticonvulsant drugs often show activity in pain models, and compound 30 was also proven effective in the formalin test of tonic pain, the capsaicin-induced pain model, and the oxaliplatin (OXPT)-induced neuropathic pain model in mice. Our studies showed that the most plausible mechanism of action of 30 involves inhibition of calcium currents mediated by Cav_1.2 (L-type) channels. Importantly, 30 revealed high metabolic stability on human liver microsomes, negligible hepatotoxicity, and relatively weak inhibition of CYP3A4, CYP2D6, and CYP2C9 isoforms of cytochrome P450, compared to reference compounds. The promising in vivo activity profile and drug-like properties of compound 30 make it an interesting candidate for further preclinical development.