Biology subjects

Malovic, E.

Publications and source records attributed to Malovic, E..

6 recordsLinked to original sources

bioRxiv2026

Comparative Proteomic Analysis of Environmental and Genetic Models of Parkinsons Disease Highlights the Role of Purine Metabolism.

Parkinsons Disease (PD) is the second most common neurodegenerative disease, with many cases being attributed to environmental contaminant exposures. Paraquat (PQ), is a pesticide and environmental neurotoxicant that has been strongly associated with increased risk of PD. PQ is known to be a weak inhibitor of complex I of the electron transport chain, and while its acute toxicity is well understood, the underlying mechanism by which PQ exposure contributes to PD pathophysiology remains unclear. Additionally, the mechanism of PQ neurotoxicity has yet to be effectively compared and related to genetic forms of PD. Given that PD is a heterogeneous disease with both genetic and environmental determinants, we sought to systematically compare the proteomic changes that occur in different genetic and environmental models of PD. In this study, we leveraged untargeted omics approaches to differentiate between systemic, peripheral, and CNS-specific changes in the proteome. We did this by performing a comparative proteomic analysis on the heads and bodies of Drosophila models of PQ ingestion and neuronal -synuclein expression in males. Additionally, we validated the findings with metabolomic analysis of male and female brain stems from a murine PQ inhalation model using C57BL/6J mice. Our findings indicate shared dysregulated pathways across all models, highlighting similar mechanisms of action. Specifically, we identified a glia-specific role in purine nucleotide metabolism upstream of inosine catabolism, which may protect against PQ neurotoxicity. This work identifies potential early points for biomarker detection and potential targets for drug intervention. Significance StatementNeurodegenerative diseases such as Parkinsons disease (PD) pose a growing public health burden, yet disease-modifying therapies remain limited due to lack of mechanistic understanding and disease heterogeneity. Both genetic and environmental factors contribute to PD, complicating the identification of shared therapeutic targets. Here, we identify a convergent pathway common to genetic and environmental models of Parkinsonism that not only affects the brain but also systemically. Using integrated metabolomics, proteomics, and genome-scale metabolic modeling, we demonstrate that purine metabolism is dysregulated across models. Reverse genetic screening of key enzymes in this pathway mitigates locomotor deficits induced by neurotoxic pesticide exposure in Drosophila. These findings reveal a shared metabolic vulnerability in PD and highlight purine metabolism as a potential therapeutic target.

neuroscience↗

bioRxiv2026

Super-resolved, three-dimensional spatial transcriptomics reveals cell-type and brain-region-specific modulation of key epitranscriptomic switches following adolescent alcohol exposure

Epitranscriptomic mechanisms dynamically regulate neuronal function through gene expression, but their precise roles in neuropsychiatric and neurological disorders remain to be fully elucidated. A major obstacle to advancing such studies is the absence of a methodology for precise, cell-type and brain-region-specific quantification of critical epitranscriptomic regulators under these complex brain conditions. To overcome this challenge, we developed a super-resolved, three-dimensional spatial transcriptomics method to quantify key epitranscriptomic switches in intact brains. Using this method, we quantified the expression of Mettl3, an N6-methyladenosine (m6A) methyltransferase enzyme recently shown to be upregulated in the amygdala after adolescent intermittent ethanol (AIE) exposure in rats. We observed a significant increase in cytoplasmic Mettl3 mRNA in neurons, but not in astrocytes or microglia, within the adult central amygdala and the CA1 and dentate gyrus of hippocampus following AIE. In contrast, no significant changes were observed across neurons, astrocytes, or microglia within the basolateral amygdala or the hippocampal CA3. Additionally, we found both the cytoplasmic density and subcellular localization of Mettl3 mRNA were dependent on the specific cell types and brain subregions examined. These results suggest that AIE increases Mettl3 expression in a highly cell-type-specific and spatially heterogeneous manner, underscoring the necessity of high-resolution spatial transcriptomics methods for studying transcriptomic and epitranscriptomic regulations under neurological conditions. Significance StatementEpitranscriptomics plays a crucial role in neuronal functions by influencing the splicing, stability, and translation of genes. However, the exact role of epitranscriptomic mechanisms, such as m6A RNA methylation, in brain disorders remains unclear, particularly in a cell-type and circuitry-specific manner. Here we developed a super-resolved, three-dimensional spatial transcriptomics method and applied it to a model of alcohol exposure. We found differential cell-type- and brain-region-specific modulation of Mettl3, a key m6A enzymatic switch, across major brain regions following adolescent intermittent ethanol exposure in adulthood. Our findings, coupled with our pipeline, are expected to address existing methodological limitations and knowledge gaps, thereby accelerating brain transcriptomic and epitranscriptomic studies under various psychiatric and neurological conditions.

neuroscience↗

bioRxiv2025

KCa3.1 Contributes to Neuroinflammation and Nigral Dopaminergic Neurodegeneration in Experimental models of Parkinson's Disease

Chronic neuroinflammation and misfolded -synuclein (Syn) have been identified as key pathological correlates driving Parkinsons disease (PD) pathogenesis; however, the contribution of ion channels to microglia activation in the context of -synucleinopathy remains elusive. Herein, we show that KCa3.1, a calcium-activated potassium channel, is robustly upregulated within microglia in multiple preclinical models of PD and, most importantly, in human PD and dementia with Lewy bodies (DLB) brains. Pharmacological inhibition of KCa3.1 via senicapoc or TRAM-34 inhibits KCa3.1 channel activity and the associated reactive microglial phenotype in response to aggregated Syn, as well as ameliorates of PD like pathology in diverse PD mouse models. Additionally, proteomic and transcriptomic profiling of microglia revealed that senicapoc ameliorates aggregated Syn-induced, inflammation-associated pathways and dysregulated metabolism in primary microglial cells. Mechanistically, FYN kinase in a STAT1 dependent manner regulates KCa3.1 mediated the microglial reactive activation phenotype after -synucleinopathy. Moreover, reduced neuroinflammation and subsequent PD-like neuropathology were observed in SYN AAV inoculated KCa3.1 knockout mice. Together, these findings suggest that KCa3.1 inhibition represents a novel therapeutic strategy for treating patients with PD and related -synucleinopathies.

neuroscience↗

bioRxiv2025

Exploring the Role of Kv1.3 and MAPK14 in Mediating Microglial Oxidative Stress and Neuroinflammation Following Organic Dust Exposure

BackgroundAgricultural contaminants, including inhaled organic dust (OD) and gases, are known to cause inflammation in the lungs and the brain. We investigated the role of the potassium channel Kv1.3 in organic dust (OD)-induced neuroinflammation models. Kv1.3 channels play a multifaceted role in microglial immune modulation, cancer, neurodegenerative diseases, and constitute a potential therapeutic target. MethodsWe used in vivo (C57BL/6 mice), in vitro (microglial cell line, primary microglia), and ex vivo (brain slice culture) models of OD-induced neuroinflammation. A sterile OD extract (ODE) was prepared, and mice were exposed to either normal saline or ODE intra-nasally for 5 weeks (5 days/week) to simulate an occupational exposure scenario. Primary microglia were isolated from neonatal mice for total RNA sequencing (RNA-seq). The ODE-induced expression of Kv1.3 was quantified using in vitro and ex vivo models with and without PAP-1 treatments. Exposure-induced changes in cytokines and reactive species markers were measured. Using western blot, we quantified phosphorylated p38 MAPK14 (p-p38 MAPK) and NOX2. We measured the currents through Kv1.3 channels using a microglial patch-clamp assay. ResultsExposure to ODE increased the expression of Kv1.3 and p-p38 MAPK in mouse microglia without affecting the Kv1.3 currents at the cell surface. Exposure increased the levels of inflammatory cytokines and NOX2. Kv1.3 inhibition with PAP-1 decreased inflammatory markers (TNF- and IL-6), levels of Kv1.3, p-p38 MAPK, NOX2, and nitrites. ConclusionOur study revealed that pharmacological inhibition of Kv1.3 potassium channels reduces ODE-induced neuroinflammation by decreasing inflammatory and oxidative stress markers.

pharmacology and toxicology↗

bioRxiv2024

Mitochondrial Stress Disassembles Nuclear Architecture through Proteolytic Activation of PKCδ and Lamin B1 Phosphorylation in Neuronal Cells: Implications for Pathogenesis of Age-related Neurodegenerative Diseases

Mitochondrial dysfunction and oxidative stress are hallmarks of pathophysiological processes in age-related neurodegenerative diseases including Parkinsons, Alzheimers and Huntingtons diseases. Neuronal cells are highly vulnerable to mitochondrial stress, however, the cellular and molecular mechanisms underlying the enhanced vulnerability are not well understood. Previously, we demonstrated that the novel PKC isoform PKC{delta} is highly expressed in dopamin(DA)ergic neurons and plays a key role in inducing apoptotic cell death during neurotoxic stress via caspase-3-mediated proteolytic activation. Herein, we further uncovered a key downstream molecular event of PKC{delta} signaling following mitochondrial dysfunction that governs neuronal cell death by dissembling nuclear architecture. Exposing N27 DAergic cell line to the mitochondrial complex-1 inhibitor tebufenpyrad induced PKC{delta} phosphorylation at the T505 activation loop accompanied by caspase-3-dependent proteolytic activation of the kinase. Subcellular analysis using high-resolution 3D confocal microscopy revealed that proteolytically activated cleaved PKC{delta} translocates to the nuclear compartment, colocalizing with Lamin B1. Electron microscopy also enabled the visualization of nuclear membrane damage triggered by subjecting the DAergic neuronal cells by Tebufenpyrad (Tebu) toxicity. In silico analyses identified that the threonine site on Lamin B1 (T575) is likely phosphorylated by PKC{delta}, suggesting that Lamin B1 serves as a key downstream target of the kinase. Interestingly, N27 DAergic cells stably expressing the PKC{delta} proteolytic cleavage site-resistant mutant failed to induce nuclear damage, PKC{delta} activation, and Lamin B1 phosphorylation. Furthermore, CRISPR/Cas9-based stable knockdown of PKC{delta} greatly attenuated Tebu-induced Lamin B1 phosphorylation. Also, studies using Lamin B1T575G mutated at phosphorylation and PKC{delta}-{Delta}NLS-overexpressing N27 cells showed that PKC{delta} activation and translocation to the nuclear membrane are critically required for phosphorylating Lamin B1 at T575 to induce nuclear membrane damage during Tebu insult. Additionally, Tebu failed to induce Lamin B1 damage and Lamin B1 phosphorylation in organotypic midbrain slices cultured from PKC{delta}-/- mouse pups. More importantly, we observed higher PKC{delta} activation, Lamin B1 phosphorylation and Lamin B1 loss in nigral DAergic neurons from the postmortem brains of PD patients as compared to age-matched healthy control brains, thus providing translational relevance of our finding. Collectively, our data reveal that PKC{delta} functions as a Lamin B1 kinase to disassemble the nuclear membrane during the neuronal cell death process triggered by mitochondrial stress. This mechanistic insight may have important implications for the etiology of age-related neurodegenerative diseases resulting from mitochondrial dysfunction as well as for the development of novel treatment strategies.

neuroscience↗

bioRxiv2024

Epitranscriptomic Reader YTHDF2 Regulates SEK1(MAP2K4)-JNK-cJUN Inflammatory Signaling in Astrocytes during Neurotoxic Stress

As the most abundant glial cells in the CNS, astrocytes dynamically respond to neurotoxic stress, however, the key molecular regulators controlling the inflammatory status of these sentinels during neurotoxic stress have remained elusive. Herein, we demonstrate that the m6A epitranscriptomic mRNA modification tightly regulates the pro-inflammatory functions of astrocytes. Specifically, the astrocytic neurotoxic stresser, manganese (Mn), downregulated the m6A reader YTHDF2 in human and mouse astrocyte cultures and in the mouse brain. Functionally, YTHDF2 knockdown augmented, while its overexpression dampened, neurotoxic stress induced proinflammatory response, suggesting YTHDF2 serves as a key upstream regulator of inflammatory responses in astrocytes. Mechnistically, YTHDF2 RIP-sequencing identified MAP2K4 (MKK4; SEK1) mRNA as a YTHDF2 target influencing inflammatory signaling. Our target validation revealed Mn-exposed astrocytes mediates proinflammatory response by activating the phosphorylation of SEK1, JNK, and cJUN signaling. Collectively, YTHDF2 serves a key upstream molecular switch controlling SEK1(MAP2K4)-JNK-cJUN proinflammatory signaling in astrocytes.

neuroscience↗