Biology subjects

Trushina, E.

Publications and source records attributed to Trushina, E..

14 recordsLinked to original sources

bioRxiv2026

Mitochondrial Complex I Modulator Restores Network Resilience in Advanced Alzheimer's Disease Through Metabolic Reprogramming

Mitochondrial dysfunction and lipid dysregulation are among the earliest abnormalities in Alzheimers disease (AD), yet their mechanistic interplay and therapeutic potential remain poorly understood. Here, we investigated whether restoration of mitochondrial function can reverse metabolic dysfunction and promote resilience in advanced-stage AD. Female APP/PS1 mice were treated with the brain-penetrant mitochondrial complex I (mtCI) modulator CP2 beginning at 19 months of age, when pathology and cognitive deficits were well established. To define the metabolic mechanisms underlying therapeutic response, we developed iMiceBrain, the first brain-specific genome-scale metabolic model of the mouse brain, and integrated transcriptomics, targeted metabolomics, lipidomics, and metabolic network analyses. CP2 treatment broadly reprogrammed AD-associated molecular signatures and restored pathways involved in mitochondrial function, glucose utilization, lipid metabolism, synaptic activity, and cellular stress responses. Metabolic modeling identified enhanced mitochondrial substrate flexibility, activation of fatty acid utilization, restoration of pyruvate dehydrogenase flux, and normalization of cholesterol metabolism as key features of the therapeutic response. Lipidomic analyses further demonstrated correction of disease-associated alterations in cholesteryl esters, phospholipids, and sphingolipids. Together, these findings demonstrate that mild mtCI modulation restores metabolic resilience by coordinating mitochondrial and lipid metabolism, establishing it as a disease-modifying therapeutic strategy for AD.

neuroscience↗

bioRxiv2026

A Small-Molecule Mitochondrial Complex I Modulator Improves Behavioral and Mitochondrial Dysfunction in Schizophrenia

Weak inhibition of mitochondrial complex I (mtCI) has been shown to have neuroprotective effects in cellular and animal models of Alzheimers and Huntingtons diseases, at least in part by enhancing mitochondrial biogenesis and function. Mitochondrial dysfunction has also been demonstrated in schizophrenia patients and mouse models of schizophrenia. We tested whether weak inhibition of mtCI would ameliorate mitochondrial and behavioral phenotypes in a mouse model of schizophrenia. In mice with four copies of the Gldc gene, 8 weeks of treatment with the weak mtCI inhibitor, the small-molecule tricyclic pyrone compound CP2, reversed spontaneous alternation deficits in the Y maze, startle habituation deficits, and social novelty deficits in the three-chamber social interaction test. Consistent with the mechanism of action, Western blots revealed that CP2 reverses the reduced expression of PGC-1, a master regulator of mitochondrial biogenesis, and of the VDAC1, a primary gatekeeper for the exchange of metabolites, ions, and ATP between mitochondria and the cytosol. These findings suggest that the improvement of mitochondrial function may represent a novel strategy to reverse pathophysiological and behavioral deficits in schizophrenia.

neuroscience↗

bioRxiv2026

Discovery and Preclinical Validation of a Clinically Optimized Mitochondrial Complex I Modulator for Alzheimer's Disease

Alzheimers disease (AD) is characterized by diminished capacity to mount adaptive cellular stress responses required to maintain energy homeostasis and proteostasis. An emerging therapeutic strategy is to restore adaptive stress responses by inducing mild energetic stress through inhibition of mitochondrial complex I (mtCI). However, pharmacological inhibition of the respiratory chain has remained challenging, as it can induce bioenergetic failure rather than beneficial signaling. Here, we describe C273, a brain-penetrant small molecule that delivers controlled, weak attenuation of mtCI activity to therapeutically restore endogenous adaptive stress pathways. This work establishes a first-in-class mechanism in which calibrated activation of multifaceted adaptive mechanisms enhances cellular resilience, rather than impairing mitochondrial function. Structure-activity relationship optimization yielded a compound with high potency against A{beta}-induced cellular toxicity, strong selectivity for mtCI, and favorable drug-like properties. C273 demonstrated excellent oral bioavailability, metabolic stability in mouse, rat, and human microsomes, minimal CYP liabilities, and a clean ancillary pharmacology profile in the Eurofins CEREP44 panel. In vivo, C273 readily crosses the blood-brain barrier and activates AMP-activated protein kinase (AMPK), initiating a coordinated hormetic response characterized by enhanced antioxidant defenses, suppression of inflammatory signaling, induction of autophagy, and increased mitochondrial biogenesis and turnover. Genetic deletion of AMPK1/2 abolished these responses, establishing AMPK as a critical mediator of C273 activity. Pharmacological competition experiments further confirmed the target, as pretreatment with non-toxic concentrations of rotenone blocked C273 interaction with the quinone-binding site of mtCI and eliminated its neuroprotective effects. Repeated oral administration of C273 (20-80 mg/kg/day) to wild-type mice for one month produced no detectable cardiac or hepatic toxicity, indicating a favorable in vivo safety margin. Importantly, C273 activated these mechanisms and reduced A{beta} and p-Tau levels in induced pluripotent stem cell-derived cerebral organoids from patients with sporadic AD. Collectively, these results establish controlled mtCI modulation as a therapeutic strategy and position C273 as a promising disease-modifying candidate for AD.

neuroscience↗

bioRxiv2026

Multilevel impairment of mitochondrial respiration with sex-specific signatures in inclusion body myositis

BackgroundOxidative phosphorylation (OXPHOS) is a central function and a key indicator of mitochondrial fitness, yet studies in human tissue remain limited. Inclusion body myositis (IBM) is a progressive myopathy that lies at the intersection of aging, inflammation and mitochondrial dysfunction. We aimed to perform a comprehensive profiling of mitochondrial respiration in muscle tissue from patients with IBM. MethodsA wide battery of complementary tests from RNA level to high-resolution respirometry on permeabilized muscle fibers was performed. The relationship between respiration, mitochondrial content, mitochondrial DNA (mtDNA) abnormalities and mitophagy was examined, along with the correlation with various clinical parameters to determine the clinical significance of the findings. ResultsThe study included a total of 67 patients with IBM and 45 controls. IBM muscle tissue exhibited reduced maximal respiration per tissue weight in State 3 (high substrates, high ADP) and uncoupled state with decreased coupling efficiency and higher leak control ratios. When adjusting for citrate synthase reflecting mitochondrial content, males had decreased State 3 intrinsic respiration, whereas females had greater intrinsic respiration in leak states. Complex II control ratio strongly correlated with disease duration and severity only in females. IBM was associated with decreased RNA and protein expression of OXPHOS complexes. Complex I activity was decreased mainly in females. IBM samples exhibited lower maximal H2O2 emission, accompanied by a higher total antioxidant capacity that correlated with disease duration in females. In IBM, there was decreased mtDNA content, and impaired mitophagy, both of which strongly correlated with respirometry measures and markers of disease severity, indicating these pathways are likely interconnected and of clinical significance. ConclusionIBM is characterized by multilevel impairments in mitochondrial coupling efficiency, revealing several potential therapeutic targets to improve mitochondrial fitness, while accounting for sex-specific differences.

neuroscience↗

bioRxiv2025

Mitochondrial bioenergetic signatures differentiate asymptomatic from symptomatic Alzheimer's disease

Asymptomatic Alzheimers disease (AsymAD) refers to individuals who, despite exhibiting amyloid-{beta} plaques and tau pathology comparable to Alzheimers disease (AD), maintain cognitive performance similar to cognitively normal individuals. The resilience mechanism in these AsymAD individual remains understudied. We performed a systematic analysis comparing AsymAD and AD across multiple cohorts (ROSMAP, Banner and Mount Sinai), brain regions (BA6, BA9, BA36 and BA37) and neuronal and glial cell types using proteomics and transcriptomics data. AsymAD brains exhibited preserved mitochondrial bioenergetics, characterized by enhanced oxidative phosphorylation (OXPHOS), electron transport chain (ETC) activity, fatty acid and lipid metabolism, and branched-chain amino acid (BCAA) utilization. Pathways regulating mitochondrial complex biogenesis and calcium homeostasis were also upregulated. Key mitochondrial proteins such as MRPL47, CPT2, BCAT2, and IDH2, were consistently upregulated in AsymAD, whereas MACROD1 was downregulated. At the cellular level, excitatory neurons, including superficial, mid-layer, and deep-layer subtypes, exhibited the most preserved mitochondrial function, whereas vulnerable inhibitory subtypes, including PVALB and SST neurons, showed increased cellular abundance and bioenergetic activity. In contrast, microglia and oligodendrocytes proportions were reduced in AsymAD relative to AD. Our findings identify preserved mitochondrial bioenergetics as a defining feature of resilience in AD and suggest that enhancing NADH metabolism via NAD+ precursor-based interventions may potentially help in maintaining cognitive function despite amyloid and tau pathology.

neuroscience↗

bioRxiv2025

Therapeutic assessment of a novel mitochondrial complex I inhibitor in in vitro and in vivo models of Alzheimer's disease

Despite recent approval of monoclonal antibodies that reduce amyloid (A{beta}) accumulation, the development of disease-modifying strategies targeting the underlying mechanisms of Alzheimers disease (AD) is urgently needed. We demonstrate that mitochondrial complex I (mtCI) represents a druggable target, where its weak inhibition activates neuroprotective signaling, benefiting AD mouse models with A{beta} and p-Tau pathologies. Rational design and structure-activity relationship studies yielded novel mtCI inhibitors profiled in a drug discovery funnel designed to address their safety, selectivity, and efficacy. The new lead compound C458 is highly protective against A{beta} toxicity, has favorable pharmacokinetics, and has minimal off-target effects. C458 exhibited excellent brain penetrance, activating neuroprotective pathways with a single dose. Preclinical studies in APP/PS1 mice were conducted via functional tests, metabolic assessment, in vivo 31P- NMR spectroscopy, blood cytokine panels, ex vivo electrophysiology, and Western blotting. Chronic oral administration improved long-term potentiation, reduced oxidative stress and inflammation, and enhanced mitochondrial biogenesis, antioxidant signaling, and cellular energetics. These studies provide further evidence that the restoration of mitochondrial function and brain energetics in response to mild energetic stress represents a promising disease- modifying strategy for AD.

neuroscience↗

bioRxiv2024

Mitochondria-centered metabolomic map of inclusion body myositis: sex-specific alterations in central carbon metabolism

BackgroundInclusion body myositis (IBM) is a disease of aging characterized by progressive muscle loss. Despite its positioning at the intersection of aging, mitochondrial dysfunction and chronic inflammation, limited studies have evaluated the underlying metabolic disturbances in IBM. ObjectiveTo investigate the mitochondria-centered metabolomic map of IBM in muscle tissue, highlighting sex-specific differences, and to determine the correlation of the changes in metabolites and gene expression with clinical parameters. Methods37 IBM patients and 22 controls without a myopathy were included. All participants had bulk RNA sequencing performed previously. Clinical parameters included age at biopsy, disease duration, manual motor test (MMT) score, and modified Rankin scale (MRS). A complementary battery of metabolomics platforms was used, including untargeted metabolomics, Agilent dMRM Database and Method platform, and targeted metabolomics. Metabolite levels and RNA-metabolomics integrated modules were correlated with clinical parameters. ResultsMuscle samples from IBM patients had elevated TCA cycle intermediates with concomitant increase in anaplerotic amino acids, suggesting increased anaplerosis into the cycle. There was a decrease in upper glycolysis intermediates and an increase in most of the pentose phosphate pathway (PPP) metabolites. The PPP is the main source of NAPDH, a main antioxidant, and ribose-5-P a precursor of nucleic acids. There were marked sex-specific differences in the acylcarnitine profile, with a decrease in short-chain acylcarnitines only in males. Lastly, there was an increase in nucleic acid bases and a decrease in nucleotides. Several metabolites from various pathways had significant correlations with various clinical parameters, with the most pronounced sex-specific differences observed in correlations with acylcarnitines. RNA-metabolomics integration identified 4 modules, with the strongest correlation observed between one module and sex. The MMT score, an indicator of disease severity, showed a strong correlation with 3 modules. There were major sex specific differences with males having relatively similar correlation to the grouped (both sexes) analysis, while females had no significant correlation with any of the modules. ConclusionTaken together, our findings identified clinically significant alterations in central carbon metabolism in IBM, with major differences between males and females. Future studies are needed to determine the role of the detected metabolic alterations in IBM pathogenesis and track the changes longitudinally over the disease course.

neuroscience↗

bioRxiv2024

Ndufs4 knockout induces transcriptomic signatures of Alzheimer's Diseases that are partially reversed by mitochondrial complex I inhibitor

Mitochondrial dysfunction is well documented in Alzheimers Disease (AD). However, whether it instigates the onset of AD remains unclear. We demonstrate that a reduction of complex I activity in wild type (WT) mice caused by a global knockout of Ndufs4, an accessory mitochondrial complex I subunit, was sufficient to induce transcriptomic changes in the brain reminiscent of those observed in AD patients and familial mouse models of AD. Reduced complex I activity affected expression of genes in the networks related to mitochondrial homeostasis, neuronal and synaptic function. Transcriptomic signatures in male and female Ndufs4-/-mice reflected a different severity of AD phenotype. Unexpectedly, these changes were partially rescued by a neuroprotective small molecule mild complex I inhibitor CP2. Consistent with studies in AD mice, CP2 treatment in Ndufs4-/- mice augmented the expression of genes associated with mitochondrial biogenesis and turnover, synaptic activity, autophagy, redox balance, and reduced expression of genes related to inflammation. Female Ndufs4-/- mice demonstrated a greater reversal of gene expression toward WT mice. These studies provide further support for mitochondria as a causative factor of AD pathophysiology and complex I as a putative therapeutic target.

neuroscience↗

bioRxiv2022

OPA1 Downregulation in Skeletal Muscle Induces MERC formation in an ATF4-Dependent Manner

Mitochondria and endoplasmic reticulum (ER) contact sites (MERCs) are protein- and lipid-enriched hubs that mediate interorganellar communication by contributing to the dynamic transfer of Ca2+, lipid, and other metabolites between these organelles. Defective MERCs are associated with cellular oxidative stress, neurodegenerative disease, and cardiac and skeletal muscle pathology via mechanisms that are poorly understood. We previously demonstrated that skeletal muscle-specific knockdown (KD) of the mitochondrial fusion mediator optic atrophy 1 (OPA1) induced ER stress and correlated with an induction of Mitofusin-2, a known MERC protein. In the present study, we tested the hypothesis that Opa1 downregulation in skeletal muscle cells alters MERC formation by evaluating multiple myocyte systems, including from mice and Drosophila, and in primary myotubes. Our results revealed that OPA1 deficiency induced tighter and more frequent MERCs in concert with a greater abundance of MERC proteins involved in calcium exchange. Additionally, loss of OPA1 increased the expression of activating transcription factor 4 (ATF4), an integrated stress response (ISR) pathway effector. Reducing Atf4 expression prevented the OPA1-loss-induced tightening of MERC structures. OPA1 reduction was associated with decreased mitochondrial and sarcoplasmic reticulum, a specialized form of ER, calcium, which was reversed following ATF4 repression. These data suggest that mitochondrial stress, induced by OPA1 deficiency, regulates skeletal muscle MERC formation in an ATF4-dependent manner.

biophysics↗

bioRxiv2021

A comprehensive approach for artifact-free sample preparation and assessment of mitochondrial morphology in tissue and cultured cells

Mitochondrial dynamics (fission, fusion, and the formation of nanotunnels) and morphology are very sensitive to the cellular environment. Mitochondria may be adversely affected by oxidative stress, changes in calcium levels, and hypoxia. Investigating the precise relationship between organelle structure and function requires methods that can adequately preserve mitochondria while providing accurate, quantitative measurements of morphological attributes. Here, we demonstrate a practical approach for preserving and measuring fine structural changes using two-dimensional, high-resolution electron micrographs. This approach is further applicable for three-dimensional volume renderings, obtained using serial block-face and focused ion beam-scanning electron microscopy, highlighting the specific advantages of these techniques. Additionally, this study defines a set of quantifiable metrics that can be applied to measure mitochondrial architecture and other organellar structures. Finally, we validated specimen preparation methods that avoid the introduction of morphological artifacts that may interfere with mitochondrial appearance and do not require whole-animal perfusion.

cell biology↗

bioRxiv2020

Partial Inhibition of Mitochondrial Complex I Reduces Tau Pathology and Improves Energy Homeostasis and Synaptic Function in 3xTg-AD Male and Female Mice

BackgroundAccumulation of hyperphosphorylated Tau (pTau) protein is associated with synaptic dysfunction in Alzheimers disease (AD). We previously demonstrated that neuroprotection in familial mouse models of AD could be achieved by targeting mitochondria complex I (MCI) and activating the adaptive stress response. Efficacy of this strategy on pTau-related pathology remained unknown. ObjectiveTo investigate the effect of specific MCI inhibitor tricyclic pyrone compound CP2 on pTau levels, memory function, long term potentiation (LTP), and energy homeostasis in 18-month-old 3xTg-AD mice and explore the potential mechanisms. MethodsCP2 was administered to male and female 3xTg-AD mice from 3.5 - 18 months of age. Cognitive function was assessed using the Morris water maze test. Glucose metabolism was measured in periphery using a glucose tolerance test and in the brain using fluorodeoxyglucose F18 positron-emission tomography (FDG-PET). LTP was evaluated using electrophysiology in the hippocampus. The expression of key proteins associated with neuroprotective mechanisms were assessed by western blotting. ResultsChronic CP2 treatment restored synaptic activity and cognitive function, increased levels of synaptic proteins, improved glucose metabolism and energy homeostasis in male and female 3xTg-AD mice. Significant reduction of human pTau in the brain was associated with increased activity of protein phosphatase of type 2A (PP2A), reduced activity of cyclin-dependent kinase 5 (CDK5) and glycogen synthase kinase 3{beta} (GSK3{beta}). ConclusionCP2 treatment protected against synaptic dysfunction and memory impairment in symptomatic 3xTg-AD mice, and reduced levels of human pTau, indicating that targeting mitochondria with small molecule specific MCI inhibitors represents a promising strategy for AD.

neuroscience↗

bioRxiv2020

Partial inhibition of mitochondrial complex I attenuates neurodegeneration and restores energy homeostasis and synaptic function in a symptomatic Alzheimers mouse model

We demonstrate that mitochondrial respiratory chain complex I is an important small molecule druggable target in Alzheimers Disease (AD). Partial inhibition of complex I triggers the AMP-activated protein kinase-dependent signaling network leading to neuroprotection in symptomatic APP/PS1 mice, a translational model of AD. Treatment of APP/PS1 mice with complex I inhibitor after the onset of AD-like neuropathology improved energy homeostasis, synaptic activity, long-term potentiation, dendritic spine maturation, cognitive function and proteostasis, and reduced oxidative stress and inflammation in brain and periphery, ultimately blocking the ongoing neurodegeneration. Therapeutic efficacy in vivo was monitored using translational biomarkers FDG-PET, 31P NMR, and metabolomics. Cross-validation of the mouse and the human AMP-AD transcriptomic data demonstrated that pathways improved by the treatment in APP/PS1 mice, including the immune system response and neurotransmission, represent mechanisms essential for therapeutic efficacy in AD patients.

neuroscience↗

bioRxiv2020

Autophagy promotes cell and organismal survival by maintaining NAD(H) pools

Autophagy is an essential catabolic process that promotes clearance of surplus or damaged intracellular components1. As a recycling process, autophagy is also important for the maintenance of cellular metabolites during periods of starvation2. Loss of autophagy is sufficient to cause cell death in animal models and is likely to contribute to tissue degeneration in a number of human diseases including neurodegenerative and lysosomal storage disorders3-7. However, it remains unclear which of the many cellular functions of autophagy primarily underlies its role in cell survival. Here we have identified a critical role of autophagy in the maintenance of nicotinamide adenine dinucleotide (NAD+/NADH) levels. In respiring cells, loss of autophagy caused NAD(H) depletion resulting in mitochondrial membrane depolarisation and cell death. We also found that maintenance of NAD(H) is an evolutionary conserved function of autophagy from yeast to human cells. Importantly, cell death and reduced viability of autophagy-deficient animal models can be partially reversed by supplementation with an NAD(H) precursor. Our study provides a mechanistic link between autophagy and NAD(H) metabolism and suggests that boosting NAD(H) levels may be an effective intervention strategy to prevent cell death and tissue degeneration in human diseases associated with autophagy dysfunction.

cell biology↗

bioRxiv2019

The Alzheimer’s Disease Metabolome: Effects of Sex and APOE ε4 genotype

Recent studies have provided evidence that late-onset Alzheimers disease (AD) can in part be considered a metabolic disease. Besides age, female sex and APOE {varepsilon}4 genotype represent strong risk factors for AD. They also both give rise to large metabolic differences, suggesting that metabolic aspects of AD pathogenesis may differ between males and females and between APOE {varepsilon}4 carriers and non-carriers. We systematically investigated group-specific metabolic alterations by conducting stratified association analyses of 140 metabolites measured in serum samples of 1,517 AD neuroimaging initiative subjects, with AD biomarkers for A{beta} and tau pathology and neurodegeneration. We observed substantial sex differences in effects of 15 metabolites on AD biomarkers with partially overlapping differences for APOE {varepsilon}4 status groups. These metabolites highlighted several group-specific alterations not observed in unstratified analyses using sex and APOE {varepsilon}4 as covariates. Combined stratification by both variables uncovered further subgroup-specific metabolic effects limited to the group with presumably the highest AD risk: APOE {varepsilon}4+ females. Pathways linked to the observed metabolic alterations suggest that females experience more expressed impairment of mitochondrial energy production in AD than males. These findings indicate that dissecting metabolic heterogeneity in AD pathogenesis may enable grading of the biomedical relevance of specific pathways for specific subgroups. Extending our approach beyond simple one- or two-fold stratification may thus guide the way to personalized medicine.\n\nSignificance statementResearch provides substantial evidence that late-onset Alzheimers disease (AD) is a metabolic disease. Besides age, female sex and APOE{varepsilon}4 genotype represent strong risk factors for AD, and at the same time give rise to large metabolic differences. Our systematic investigation of sex and APOE {varepsilon}4 genotype differences in the link between metabolism and measures of pre-symptomatic AD using stratified analysis revealed several group-specific metabolic alterations that were not observed without sex and genotype stratification of the same cohort. Pathways linked to the observed metabolic alterations suggest females are more affected by impairment of mitochondrial energy production in AD than males, highlighting the importance of tailored treatment approaches towards a precision medicine approach.

bioinformatics↗