Percorrer por autor "Bekman, Evguenia P."
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- Comprehensive chemical and enantiomeric characterization of commercial turpentine oils by GC–MSPublication . Pombo, Débora․S․ D․; Barra, Bárbara F․ C․; Bettencourt, Madalena; Quintas, Alexandre; Bekman, Evguenia P.; Neng, Nuno R.Recent reports from families of individuals with Angelman syndrome (AS), a rare neurodevelopmental disorder characterised by severe neurological impairment and epilepsy, have described perceived neurological improvements following the topical application of a commercial turpentine oil (TO). These observations prompted the present analytical study, which aimed to characterise and quantify the terpenoid composition of 2 commercial TOs (Diamond and Creekwood), together with 6 additional commercial TOs, using gas chromatography-mass spectrometry (GC–MS). Analysis of 6 TOs reported to originate from Pinus pinaster revealed similar combined percentages of α- and β-pinene (≈75%), except for one oil that exhibited a more complex profile, a lower α-pinene content (≈30%), and the presence of eucalyptol, which is uncommon in TOs from this species. The Creekwood oil contained a higher proportion of α-pinene (≈76%) and a markedly lower β-pinene content (≈3%) than the Diamond oil (≈62% and ≈26%, respectively). Chiral GC–MS analysis further revealed contrasting enantiomeric distributions, with (–)-α-pinene predominating in the Diamond oil and (+)-α-pinene in the Creekwood oil, while (–)-β-pinene predominated in both samples. For quantitative analysis, the analytical method was successfully validated, demonstrating suitable detection (1.5–5.0 mg/L) and quantification (5.0–16.7 mg/L) limits, good linearity (r2>0.991), and acceptable precision and accuracy (<15%). These findings demonstrate substantial chemical variability among commercial TOs and provide a framework for future studies on the biological effects of pine resin terpenoids in neuronal models relevant to AS.
- hiPSC-based model of prenatal exposure to cannabinoids: effect on neuronal differentiationPublication . Miranda, Cláudia C.; Barata, Tiago; Vaz, Sandra H.; Ferreira, Carla; Quintas, Alexandre; Bekman, Evguenia P.Phytocannabinoids are psychotropic substances of cannabis with the ability to bind endocannabinoid (eCB) receptors that regulate synaptic activity in the central nervous system (CNS). Synthetic cannabinoids (SCs) are synthetic analogs of Δ9-tetrahydrocannabinol (Δ9-THC), the psychotropic compound of cannabis, acting as agonists of eCB receptor CB1. SC is an easily available and popular alternative to cannabis, and their molecular structure is always changing, increasing the hazard for the general population. The popularity of cannabis and its derivatives may lead, and often does, to a child’s exposure to cannabis both in utero and through breastfeeding by a drug-consuming mother. Prenatal exposure to cannabis has been associated with an altered rate of mental development and significant changes in nervous system functioning. However, the understanding of mechanisms of its action on developing the human CNS is still lacking. We investigated the effect of continuous exposure to cannabinoids on developing human neurons, mimicking the prenatal exposure by drug-consuming mother. Two human induced pluripotent stem cells (hiPSC) lines were induced to differentiate into neuronal cells and exposed for 37 days to cannabidiol (CBD), Δ9-THC, and two SCs, THJ-018 and EG-018. Both Δ9-THC and SC, at 10 μM, promote precocious neuronal and glial differentiation, while CBD at the same concentration is neurotoxic. Neurons exposed to Δ9-THC and SC show abnormal functioning of voltage-gated calcium channels when stimulated by extracellular potassium. In sum, all studied substances have a profound impact on the developing neurons, highlighting the importance of thorough research on the impact of prenatal exposure to natural and SC.
- A stem cell-based toolkit to model Angelman syndrome caused by paternal uniparental disomy of chromosome 15Publication . Mateus, Francisca Cazaux; Santos, João Camões dos; Arez, Maria; Bekman, Evguenia P.; Rocha, Simão T. daAngelman syndrome is a rare neurodevelopmental disorder caused by the loss of function of the maternally inherited UBE3A gene within the chr15q11-q13 region. This gene is subjected to a tissue-specific form of genomic imprinting leading to the silencing of the paternal allele in neurons. Angelman syndrome can result from various (epi)genetic mechanisms, with paternal uniparental disomy of chromosome 15 (patUPD15) being one of the rarest and least studied due to the absence of suitable models. To address this gap, we generated three independent induced pluripotent stem cell (iPSC) lines from individuals with Angelman syndrome caused by patUPD15, alongside genetically matched unaffected familial controls. Peripheral blood mononuclear cells (PBMCs) were reprogrammed into iPSCs using a non-integrative Sendai virus-based approach expressing the Yamanaka factors. All iPSC lines underwent rigorous quality control, confirming stem cell identity, trilineage differentiation potential, and genetic and epigenetic integrity. This newly established iPSC toolkit provides a powerful platform to investigate the molecular underpinnings of Angelman syndrome caused by patUPD15, paving the way for future translational research and therapeutic development tailored for this understudied form of the disorder.