Biology subjects

Lefterov, I.

Publications and source records attributed to Lefterov, I..

4 recordsLinked to original sources

bioRxiv2026

Integration of transcriptional signatures from brain tissue and plasma extracellular vesicles of a preclinical tauopathy mouse model

Tauopathies, including Alzheimers disease, involve progressive neurodegeneration and sustained neuroinflammation. We present a multi-compartment transcriptomic atlas of 9.6-month-old PS19 tauopathy mice compared with wild-type (WT) controls (n=8/group), profiling cortical mRNA, cortical non-coding RNA (ncRNA), and plasma small extracellular vesicle (pEV) ncRNA. In the PS19 cortex, mRNA sequencing identified 917 differentially expressed genes (DEGs), with microglial deconvolution revealing a robust transition toward disease-associated microglia (DAM) gene signature and downregulation of genes involved in oxidative phosphorylation and cholesterol biosynthesis relative to WT. Cortical ncRNA profiling identified 466 differentially expressed ncRNAs, primarily circular RNAs (circRNAs; n=331). In pEVs, 822 ncRNAs were differentially abundant, of which 657 circRNAs were identified in PS19 compared to WT mice. Cross-compartment integration demonstrated that pEV miRNA gene targets functionally mirrored genes involved in the brains inflammatory and metabolic failure. We identified a core shared signature of 33 ncRNAs, including miR-5114 (up in brain, down in pEV), circ_0008242 and circ_0002153 (up in brain and pEV), and circ_0007688 (down in brain and pEV) differentially enriched across both brain and periphery in PS19 compared to WT mice. These results demonstrate that the pEV non-coding landscape effectively tracks central tau-mediated changes in the brain transcriptional response. This study identifies circRNAs as the most numerically perturbed ncRNA class and provides a foundation for non-invasive biomarker development in tauopathy.

neuroscience↗

bioRxiv2026

A novel technique for monitoring Alzheimer's disease associated changes in brain-derived extracellular vesicle cargos in mouse models

Extracellular vesicles (EVs) are critical mediators of intercellular communication, carrying molecular cargos such as small noncoding RNAs (ncRNAs) that reflect the physiological and pathological state of their cells of origin. However, studying brain-derived EVs has been challenging due to the blood-brain barrier. Here, we optimized and validated an open-flow microdialysis (OFM) protocol for sampling EVs directly from brain interstitial fluid (ISF) in wild-type and APP/PS1 transgenic mice. Ex-vivo validation using plasma EVs demonstrated that OFM effectively captures the full EV population. In-vivo cerebral OFM (cOFM) enabled successful collection of brain ISF EVs, which were characterized by nanoparticle tracking analysis (NTA), electron microscopy, and western blotting, confirming their similarity to EVs isolated directly from brain tissue and plasma. Identification of small ncRNA cargos revealed that EVs sampled from brain ISF by cOFM were enriched in brain-specific signatures, many of which are associated with neuronal cell populations and biological functions. Furthermore, we observed a unique small ncRNA signature from the brain ISF EVs in the Alzheimers disease preclinical model compared to wild-type mice. These small ncRNAs were associated with genes considered important in biological functions associated with neurodegeneration. Our findings demonstrate that cOFM is a powerful tool for in-vivo sampling of brain EVs and highlight the unique molecular landscape of ISF EV small ncRNA cargos. This study offers new opportunities for biomarker discovery and mechanistic insights into neurodegenerative diseases, such as Alzheimers disease.

neuroscience↗

bioRxiv2025

Brain single-cell transcriptional responses to bexarotene-activated RXR in Alzheimer's disease model

Pharmacological activation of brain Retinoid X Receptors (RXRs) enhances cognition and facilitates amyloid-beta (A{beta}) clearance in Alzheimers disease (AD) mouse models, partly by upregulating Apolipoprotein E (Apoe), a major AD genetic risk factor. However, the specific cellular contributions to these effects are unclear. Here, we used single-cell transcriptomic profiling to investigate cell subpopulation-specific responses to bexarotene, an RXR agonist, in APP/PS1 mice. Our analysis revealed that bexarotene activated cholesterol biosynthesis and lipid metabolism transcriptional programs in homeostatic astrocytes and oligodendrocytes. Astrocytes also upregulated neurodevelopmental genes, while oligodendrocytes and endothelial cells showed enhanced protein folding and cellular growth pathways. Bexarotene further modulated immune responses, promoting A{beta}-responsive signatures in disease-associated microglia and reactive astrocytes, while dampening pro-inflammatory responses in homeostatic microglia and endothelial cells. Furthermore, Apoe expression was significantly elevated across multiple cell types, especially in microglia and oligodendrocytes. Cell-cell communication analysis highlighted increased astrocyte-centered signaling, with APOE-driven pathways emerging as a prominent mediator. These findings clarify the cell-specific complexity of RXR-mediated regulation and underscore APOE as a central mediator of bexarotenes neuroprotective effects. This study provides mechanistic insights into RXR-targeted interventions, and supports APOE-associated pathways as promising therapeutic targets in AD.

neuroscience↗

bioRxiv2025

Transcriptomic Response to Neuromuscular Electrical Stimulation in Muscle, Brain and Plasma EVs in WT and Klotho-deficient Mice

Neuromuscular electrical stimulation (NMES) was shown to improve motor activities and daily living. Prior studies indicated extracellular vesicles (EVs) play a role in cellular communication. Here, we evaluated transcriptomic profiles of tibialis anterior muscle, brain, and plasma-derived EVs following NMES of WT and Klotho heterozygous (KlHET). Muscle RNA-seq data demonstrated that in both genotypes the most upregulated functional categories were related to glucose metabolism and response to insulin with pathways uniquely affected in each genotype. There was a similarity of non-coding RNA transcriptome of plasma EVs with functional patterns suggesting response to oxygen and insulin, and long-term synaptic potentiation. Brain transcriptome showed little functional overlap between WT and KlHET mice. In WT, brain upregulation of genes were related to blood flow and cell adhesion processes while KlHET shows upregulation of immune function. Results indicate that similar metabolic function is impacted in the location of stimulation, but the distal impact of stimulation on the brain is associated with Klotho deficiency.

genomics↗