The recent identification of plasma membrane (Ca²⁺)-ATPase (PMCA)-Neuroplastin (Np) complexes has renewed attention on cell regulation of cytosolic calcium extrusion, which is of particular relevance in neurons. Here, we tested the hypothesis that PMCA-Neuroplastin complexes exist in specific ganglioside-containing rafts, which could affect calcium homeostasis. We analyzed the abundance of all four PMCA paralogs (PMCA1-4) and Neuroplastin isoforms (Np65 and Np55) in lipid rafts and bulk membrane fractions from GM2/GD2 synthase-deficient mouse brains. In these fractions, we found altered distribution of Np65/Np55 and selected PMCA isoforms, namely PMCA1 and 2. Cell surface staining and confocal microscopy identified GM1 as the main complex ganglioside co-localizing with Neuroplastin in cultured hippocampal neurons. Furthermore, blocking GM1 with a specific antibody resulted in delayed calcium restoration of electrically evoked calcium transients in the soma of hippocampal neurons. The content and composition of all ganglioside species were unchanged in Neuroplastin-deficient mouse brains. Therefore, we conclude that altered composition or disorganization of ganglioside-containing rafts results in changed regulation of calcium signals in neurons. We propose that GM1 could be a key sphingolipid for ensuring proper location of the PMCA-Neuroplastin complexes into rafts in order to participate in the regulation of neuronal calcium homeostasis.

Gangliosides, amphiphilic glycosphingolipids, tend to associate laterally with other membrane constituents and undergo extensive interactions with membrane proteins in cis or trans configurations. Studies of human diseases resulting from mutations in the ganglioside biosynthesis pathway and research on transgenic mice with the same mutations implicate gangliosides in the pathogenesis of epilepsy. Gangliosides are reported to affect the activity of the Na⁺/K⁺-ATPase, the ubiquitously expressed plasma membrane pump responsible for the stabilization of the resting membrane potential by hyperpolarization, firing up the action potential and ion homeostasis. Impaired Na⁺/K⁺-ATPase activity has also been hypothesized to cause seizures by several mechanisms. In this review we present different epileptic phenotypes that are caused by impaired activity of Na⁺/K⁺-ATPase or changed membrane ganglioside composition. We further discuss how gangliosides may influence Na⁺/K⁺-ATPase activity by acting as lipid sorting machinery providing the optimal stage for Na⁺/K⁺-ATPase function. By establishing a distinct lipid environment, together with other membrane lipids, gangliosides possibly modulate Na⁺/K⁺-ATPase activity and aid in “starting up” and “turning off” this vital pump. Therefore, structural changes of neuronal membranes caused by altered ganglioside composition can be a contributing factor leading to aberrant Na⁺/K⁺-ATPase activity and ion imbalance priming neurons for pathological firing.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with heterogeneous clinical presentation. Diagnosing ASD is complex, and the criteria for diagnosis, as well as the term ASD, have changed during the last decades. Diagnosis is made based on observation and accomplishment of specific diagnostic criteria, while a particular biomarker of ASD does not yet exist. However, studies universally report a disequilibrium in membrane lipid content, pointing to a unique neurolipid signature of ASD. This review sheds light on the possible role of cholesterol and gangliosides, complex membrane glycosphingolipids, in the development of ASD. In addition to maintaining membrane integrity, neuronal signaling, and synaptic plasticity, these lipids play a role in neurotransmitter release and calcium signaling. Evidence linking ASD to lipidome changes includes low cholesterol levels, unusual ganglioside levels, and unique metabolic profiles. ASD symptoms may be mitigated with therapeutic interventions targeting the lipid composition of membranes. However, restoring membrane equilibrium in the central nervous system remains a challenge. This review underscores the need for comprehensive research into lipid metabolism to uncover practical insights into ASD etiology and treatment as lipidomics emerges as a major area in ASD research.

CYP2D6 is a highly polymorphic gene whose variations affect its enzyme activity. To assess whether the specific population history of Roma, characterized by constant migrations and endogamy, influenced the distribution of alleles and thus phenotypes, the CYP2D6 gene was sequenced using NGS (Next Generation Sequencing) method-targeted sequencing in three groups of Croatian Roma (N = 323) and results were compared to European and Asian populations. Identified single nucleotide polymorphisms (SNPs) were used to reconstruct haplotypes, which were translated into the star-allele nomenclature and later into phenotypes. A total of 43 polymorphic SNPs were identified. The three Roma groups differed significantly in the frequency of alleles of polymorphisms 6769 A > G, 6089 G > A, and 5264 A > G (p < 0.01), as well as in the prevalence of the five most represented star alleles: *1, *2, *4, *10, and *41 (p < 0.0001). Croatian Roma differ from the European and Asian populations in the accumulation of globally rare SNPs (6089 G > A, 4589 C > T, 4622 G > C, 7490 T > C). Our results also show that demographic history influences SNP variations in the Roma population. The three socio-culturally different Roma groups studied differ significantly in the distribution of star alleles, which confirms the importance of a separate study of different Roma groups.

Epithelial to mesenchymal transition (EMT) plays a critical role in tumor progression and metastasis, including in gliomas. To examine and interpret data on major genes involved in EMT and associate their changes with low-grade (LGG) and/or high-grade (HGG) gliomas, data from the cBioPortal—a publicly available database for tumor genomics and transcriptomics, were collected for 13 genes: CDH1, CDH2, CTNNB1, LEF1, NOTCH1, SNAI1, SNAI2, SOX2, TJP1/ZO1, TWIST1, VIM, ZEB1, and ZEB2. The dataset included mutations, copy number alterations (CNA), and changes in transcript levels reported for each gene. The genes were additionally validated by gene expression on the GlioVis portal, STRING protein network analysis, survival analysis, and experimentally with qRT-PCR. Glioblastoma and diffuse glioma harbored changes in all 13 analyzed genes, while anaplastic oligodendroglioma and anaplastic astrocytoma in 46.15%, oligodendroglioma in 23.08%, and oligoastrocytoma in 15.38%. NOTCH1 and SOX2 were most affected by changes. The NOTCH1 gene was statistically more frequently changed compared to CDH1, CTNNB1, and ZEB1 (p < 0.05). The virtual study showed that alterations in NOTCH1 and LEF1 were associated with LGG, while alterations in CDH1, CTNNB1, TJP1, TWIST1, SOX2, VIM, ZEB1, and ZEB2 were associated with HGG. Differential expression analysis stratified for IDH1 mutations showed that IDH1-mutant glioblastoma had significantly lower CDH2, LEF1 and SNAI1 expression, and higher ZEB1. Gene expression in different glioblastoma subtypes showed that the TJP1/ZO1 gene was associated with the classical subtype, while ZEB2 was associated with the proneural subtype. qRT-PCR confirmed GlioVis mRNA expression data for NOTCH1, SOX2, CDH1, CTNNB1, TJP1/ZO-1, VIM, TWIST1, and partially for SNAI1 (SNAIL), SNAI2, and CDH2. Our study shows consistent changes in genes involved in EMT in gliomas of different grades. Additional research is needed to confirm the knowledge brought by this study.

Toxic organophosphates like the nerve agent sarin readily cross the blood-brain barrier (BBB) and inhibit acetylcholinesterase (AChE), a pivotal enzyme in regulating neurotransmission by hydrolysis of acetylcholine (ACh). Elevated levels and prolonged residence time of ACh initiate seizures and activation of glial cells leading to neuroinflammation. Furthermore, AChE inhibition induces life-threatening symptoms if not treated promptly with atropine and an oxime reactivator of inhibited AChE. The oximes approved for therapy (e.g. 2-PAM) poorly cross the BBB due to their permanent positive charge and do not restore synaptic AChE activity, leaving the brain vulnerable to long-term damage. In this study, we investigated whether treatment with the centrally-active oxime RS194B acts protectively on the brain of mice exposed to sarin. We compared the levels of specific proteins expressed in neuronal and glial cells of mice treated with RS194B after sarin exposure with those of sarin-exposed mice, mice treated with 2-PAM, and untreated control mice. The level of Iba-1 protein was investigated as a measure of microgliosis, and GFAP of astrogliosis, whereas neuronal cell viability was assessed by detecting NeuN immunoreactivity. Our results indicated that sarin-induced gliosis was suppressed in mice treated with RS194B, in contrast to mice treated with 2-PAM. Treatment with RS194B re-established the physiological function of AChE, thus correcting the neurochemical imbalance of ACh that initiates seizures and leads to neuroinflammation. Overall, our results highlight the significance of restoring synaptic AChE activity extending beyond merely mitigating cholinergic crisis.