Biology subjects

Majerova, P.

Publications and source records attributed to Majerova, P..

6 recordsLinked to original sources

bioRxiv2026

Kynurenine pathway metabolomics in heatstroke: a validated LC-MS/MS method reveals compartment-specific neurochemical disruption in a murine model.

Heat stroke is characterized by profound central nervous system dysfunction and vascular abnormalities. Previous studies have demonstrated the marked vulnerability of the CNS to thermal stress, resulting in neuronal injury and glial activation. However, the metabolic mechanisms linking acute injury to chronic neurological long-term effects remain understood. The neuropathological changes are closely associated with neuroinflammatory and metabolic disturbances, including dysregulation of the kynurenine pathway, whose metabolites modulate neurotoxicity, neuroprotection, and immune responses. Here, we present the first comprehensive characterization of kynurenine pathway metabolomic profile across both plasma and brain tissue in a mouse model of heat stroke. Using a validated and sensitive LC-MS/MS method, we simultaneously measured and quantified 13 analytes (kynurenine, kynurenic acid, quinolinic acid, nicotinic acid, picolinic acid, xanthurenic acid, anthranilic acid, 3-hydroxykynurenine, 3-hydroxyanthranilic acid, indole-3-acetic acid, indole-3-lactic acid, 5-hydroxyindoleacetic acid and neopterin). The findings reveal a biphasic metabolic response, characterized by an acute serotonergic disruption and reduced neuroprotective capacity, followed by chronic activation of the kynurenine pathway, depletion of central serotonin metabolites, and metabolic signatures consistent with gut microbiota dysbiosis. The acute phase is marked by a transient imbalance favoring neurotoxic kynurenine pathway metabolites, whereas the chronic phase reflects sustained pathway activation. Notably, the plasma-brain dissociation of 5-hydroxyindoleacetic acid emerged as the most prominent cross-compartment finding, suggesting a potential biomarker of central serotonergic depletion and a mechanistic link between peripheral and central metabolic changes, with implications for therapeutic targeting during the subacute recovery phase.

neuroscience↗

bioRxiv2025

Alpha-synuclein overexpression triggers divergent cellular responses and post-translational modifications in SH-SY5Y and ReNcell VM models

Alpha-synuclein (-syn) overexpression models are widely used to unravel the molecular mechanisms of Parkinsons disease (PD), particularly in light of the dose-dependent transition between its physiological and toxic roles. However, existing systems rely on inducible expression, lack robust dose stratification and comparative cellular contexts. Here, we developed and characterized a panel of stable neuronal cell lines in two human cellular models (SH-SY5Y neuroblastoma cells and ReNcell VM neural progenitors) overexpressing GFP-tagged wild-type (WT) or A53T mutant -syn at low and high overexpression levels. Utilizing this framework, we demonstrated that A53T consistently induces cytotoxicity, oxidative stress and mitochondrial dysfunction in both cell types. In contrast, WT -syn had divergent effects depending on the cellular context. In SH-SY5Y cells, it enhanced mitochondrial function and viability, whereas in ReNcell VM cells, the same protein triggered mitochondrial impairment and elevated oxidative stress. This opposing metabolic response was reflected in increased respiratory activity in SH-SY5Y cells and a marked decline across WT -syn overexpressing ReNcell VM. Importantly, post-translational modification (PTM) landscape of overexpressed WT -syn varied dramatically by cell type. ReNcell VM cells exhibited more robust modifications signatures, even in the absence of overt aggregation, which highlights a cell-type-specific PTM landscape that may contribute to differential vulnerability. Our findings underscore a complex interplay between -syn dosage, mutational status, cellular environment, and PTM profiles highlighting that neuronal vulnerability in PD is context-dependent. This work establishes a modular in vitro platform for dissecting -syn pathology and testing targeted therapeutic strategies grounded in cell-type specificity.

neuroscience↗

bioRxiv2024

Development of blood-cerebrospinal fluid barrier model expressing pharmaceutically important transporters.

We have established and optimized a protocol for the high-yield isolation of primary epithelial cells from rat choroid plexus. The addition of cytosine arabinoside suppressed the growth of contaminating cells, and epithelial culture was grown into a confluent impermeable monolayer within 5-6 days after seeding. To form an in vitro blood-CSF barrier, epithelial cells were plated on inverted coated polycarbonate support of Transwell inserts. Morphologically, the polarized cells remained cuboidal in shape and expressed TJ proteins at a high rate. The filter-grown monolayers displayed transendothelial resistance (TEER) values in the range of 160 to 180 {Omega} x cm2 and remained at this level for 3 days, indicating the persistent formation of continuous TJs. The cells were able to secrete cerebrospinal fluid (CSF) actively. Epithelial cells showed expression of selective influx and efflux transporters. To conclude, our BCSFB model exhibits tight, functional barrier characteristics and shows the functional expression of the pharmaceutically important influx/efflux transporters. The recent model is suitable for in vitro investigations of BCSFB and routine pre-clinical drug discovery.

neuroscience↗

bioRxiv2023

Changes in lipid metabolism track with the progression of neurofibrillary pathology in tauopathies.

BackgroundAbnormal aggregation of tau protein that leads to brain inclusions is a common feature of neurodegenerative disorders called tauopathies. Recent evidence suggests the involvement of lipid metabolic deregulations in the pathogenesis of tauopathies. However, the role of tau protein in the regulation of lipid metabolism is much less characterized and not well understood. MethodsWe used a transgenic rat model for tauopathy to reveal metabolic alterations induced by neurofibrillary pathology. Transgenic rats express a tau fragment truncated at the N-and C-terminals. For phenotypic profiling, we performed targeted metabolomic and lipidomic analysis of brain tissue, CSF, and plasma, based on the LC-MS platform. To monitor disease progression, we employed samples from transgenic and control rats aged 4, 6, 8, 10, 12, and 14 months. To study neuron-glia interplay in lipidome changes induced by pathological tau we used well well-established multicomponent cell model system. Univariate and multivariate statistical approaches were used for data evaluation. ResultsWe showed that tau has an important role in the deregulation of lipid metabolism. In the lipidomic study, pathological tau was associated with higher production of lipids participating in protein fibrillization, membrane reorganization, and inflammation. Interestingly, significant changes have been found in the early stages of tauopathy before the formation of high-molecular-weight tau aggregates and neurofibrillary pathology. Increased secretion of pathological tau protein in vivo and in vitro induced upregulated production of phospholipids and sphingolipids and accumulation of lipid droplets in microglia. During the later stages of tauopathy, we found a connection between the transition of tau into an insoluble fraction and changes in brain metabolism. The results showed that dysregulation of lipid composition by pathological tau leads to disruption of the microenvironment and further propagation of pathology. ConclusionOur results revealed that lipid metabolism is significantly affected during different stages of tau pathology and provide new evidence that supports the contribution of pathological tau proteins in individual lipid pathways. Our data suggests that biologically active membrane lipids such as phospholipids and sphingolipids could represent new potential next-generation therapeutic targets in tauopathies.

neuroscience↗

bioRxiv2022

Analog of Kynurenic Acid Decreases Tau Pathology by Modulating Astrogliosis in Rat Model for Tauopathy.

Background and purposeKynurenines have immunomodulatory and neuroactive properties and can influence the central nervous system. Previous studies showed the involvement of the kynurenines in the pathogenesis and progression of neurodegenerative disease. In neurodegenerative disorders, including tauopathies, the tryptophan metabolism is shifted toward neurotoxic agents and the reduction of neuroprotectant products. Astrocyte-derived kynurenic acid serves as a neuroprotectant. However, systemic administration of kynurenic acid is not effective because of low permeability across the blood-brain barrier (BBB). Experimental ApproachWe used a kynurenic acid analog with similar biological activity but higher brain permeability to overcome BBB limitations. In the present study, we used amide derivate of kynurenic acid N-(2-N, N-dimethylaminoethyl)-4-oxo-1H-quinoline-2-carboxamid (KYNA-1). We administered KYNA-1 for three months to tau transgenic rats SHR-24 and analyzed the effect on tau pathology and activation of glial cells. Primary glial cell cultures were applied to identify the mechanism of the KYNA-1 effect. Key resultsKYNA-1 was not toxic to rats after chronic three-month administration. When chronically administered, KYNA-1 reduced hyperphosphorylation of insoluble tau in the brain of transgenic rats. Noteworthily, the plasma total tau was also reduced. We determined that the effect of KYNA-1 on tau pathology was induced through the modulation of glial activation. KYNA-1 inhibited LPS induced activation of astrocytes and induced transformation of microglia to M2 phenotype. Conclusion and ImplicationsWe identified that the administration of KYNA-1 reduced tau hyperphosphorylation and neuroinflammation. KYNA-1 may serve as a promising treatment for tauopathies. What is already known?O_LIStudies showed tryptophan-kynurenine pathway changes in neurodegenerative disorders including tauopathies C_LIO_LIKynurenines exert immunomodulatory and neuroactive properties and have influence on the central nervous system C_LI What does this study add?O_LIChronic administration of synthetic analog of kynurenic acid (KYNA-1) reduces tau phosphorylation and astrogliosis in a transgenic rat model for tauopathies C_LIO_LIThe analog reversed LPS-induced inflammatory changes in glial cell cultures C_LI What is the clinical significance?O_LIAdministration of KYNA-1 analog shifted the tryptophan metabolism in the neuroprotectant direction C_LIO_LINeuroprotective analogs KYNA-1 can serve as a new and effective potential therapeutic approach for tauopathies C_LI

neuroscience↗

bioRxiv2021

Second Generation Antibodies Neutralize Emerging SARS-CoV-2 Variants of Concern

Recently emerged SARS-CoV-2 variants show resistance to some antibodies that were authorized for emergency use. We employed hybridoma technology combined with authentic virus assays to develop second-generation antibodies, which were specifically selected for their ability to neutralize new variants of SARS-CoV-2. AX290 and AX677, two monoclonal antibodies with non-overlapping epitopes, exhibit subnanomolar or nanomolar affinities to the receptor binding domain of the viral Spike protein carrying amino acid substitutions N501Y, N439K, E484K, K417N, and a combination N501Y/E484K/K417N found in the circulating virus variants. The antibodies showed excellent neutralization of an authentic SARS-CoV-2 virus representing strains circulating in Europe in spring 2020 and also the variants of concern B.1.1.7 and B.1.351. Finally, the combination of the two antibodies prevented the appearance of escape mutations of the authentic SARS-CoV-2 virus. The neutralizing properties were fully reproduced in chimeric mouse-human versions, which may represent a promising tool for COVID-19 therapy.

microbiology↗