Biology subjects

Sakamoto, K.

Publications and source records attributed to Sakamoto, K..

At least 19 recordsLinked to original sources

bioRxiv2026

Fine tuning energy metabolism in skeletal muscle: Discovery of a novel autoinhibitory mechanism in the N-terminal extension of AMPKγ3

AMP-activated protein kinase (AMPK) regulates metabolism in response to metabolic stress that includes stimulating glucose uptake in skeletal muscle independently of the canonical insulin signalling pathway, positioning it as an attractive therapeutic target for insulin resistance and type 2 diabetes mellitus (T2DM). AMPK is an {beta}{gamma} heterotrimer, with multiple isoforms for each subunit enabling the formation of 12 different complexes with distinct tissue expression profiles. Among these, the 2{beta}2{gamma}3 complex is predominantly expressed in skeletal muscle, the major site of glucose disposal and a highly desirable therapeutic target for T2DM. Here, we characterise the functional role of a unique, 182 residue N-terminal extension (NTE) within {gamma}3 subunit. Deletion of the {gamma}3-NTE from 2{beta}2{gamma}3 complex increases basal AMPK activity without affecting activation by AMP or pharmacological AMPK activators, demonstrating the {gamma}3-NTE performs an autoinhibitory function. Using complementary biophysical techniques, including hydrogen-deuterium exchange-mass spectrometry, surface plasmon resonance, chemical crosslinking and co-pulldowns, we identified a 39-residue sequence in the {gamma}3-NTE (residues 129-168), that directly interacts with the C-helix of the AMPK kinase domain small lobe, a key regulatory element in many protein kinases. Using AlphaFold3, we probe the interaction predicted to take place between a {gamma}3-NTE -helix ({gamma}3-iHelix; [~]T142-E154) and the C-helix in the 2{beta}2{gamma}3 complex. These findings provide the groundwork for developing novel T2DM therapies that target AMPK activation selectively in skeletal muscle involving reversal of the {gamma}3 autoinhibition.

biochemistry↗

bioRxiv2026

No evidence for direct physical interaction of 5-HT2A-mGluR2 receptors in vitro or in vivo

Activation of mGluR2 (metabotropic glutamate receptor 2), the primary presynaptic autoreceptor for glutamate in the brain, is well established to attenuate the psychedelics-mediated behavioral and electrophysiological effects. However, the mechanisms responsible for these actions are controversial. The two competing mechanistic hypotheses have been proposed to explain this phenomenon are: (1) direct actions mediated by mGluR2/5-HT2A heterodimers, and (2) inhibition of 5-HT2A-mediated excitation of pyramidal neurons via presynaptic inhibition of glutamate release by mGluR2 receptors. Consistent with prior reports, we show that mGluR2 agonist pretreatment attenuates the head twitch response induced by the psychedelic drug 1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane (DOI) in mice engineered to express mGluR2-mCherry and 5-HT2A-eGFP-CT tagged receptors. We next employed multiple orthogonal in vivo and in vitro approaches to explore the potential for direct physical interactions between mGluR2 and 5-HT2A receptors. Across all approaches, we found no evidence for receptor colocalization or oligomerization under basal or 5-HT2A agonist-exposed conditions in vitro or in vivo. Radioligand binding and kinetic analyses revealed no evidence for mGluR2-mediated modulation of 5-HT2A ligand binding in vitro or in vivo. Collectively, our findings support models in which mGluR2 signaling modulates the activity of Gq-coupled 5-HT2A receptors in layer V pyramidal neurons, rather than models positing the requirement of mGluR2/5-HT2A multimers.

neuroscience↗

bioRxiv2026

AMPK senses cellular levels of nicotinamide adenine dinucleotide

The electron shuttle and coenzyme nicotinamide adenine nucleotide (NAD) is essential for cellular metabolism and homeostasis. NAD levels significantly fluctuate in cells, whilst several age-related diseases are associated with depletion of this metabolite. However, how NAD changes are monitored by nutrient/energy sensing signalling pathways remains poorly understood. We found that at physiological concentrations NAD controls the activity of the AMP-activated protein kinase (AMPK) in vitro and in human cells. Mechanistically, NAD binds gamma subunit of AMPK, and mutagenesis of the putative binding site renders the holoenzyme insensitive to NAD inhibition. Hyperactivation of AMPK in response to NAD depletion suppresses metabolic pathways including mammalian Target of Rapamycin Complex I (mTORC1) and autophagy. These results demonstrate that in addition to monitoring cellular energy levels AMPK functions as a NAD sensor, providing novel insight into how cells and tissues detect and respond to metabolic fluctuations with implications for stress resistance and ageing.

molecular biology↗

bioRxiv2026

Cryo-EM Structures of Brain-Derived G Protein-Coupled Receptors: The First Direct Visualization from Mammalian Brain Tissue

Glutamate is the main excitatory neurotransmitter in the brain and mediates its actions by both ionotropic (e.g. NMDA and AMPA) and metabotropic glutamate receptors (mGluRs). The Groups II and III mGluRs, which pre-synaptically inhibit glutamate release, are important for synaptic plasticity, modulating neuronal excitation, learning and memory. Our current understanding of the structural organization and dynamics of these and other mGluRs, as well as most other GPCRs, relies mainly on studies using recombinant and highly engineered systems in vitro. Here, we combine CRISPR-mediated protein tagging, proteomics and a rapid immunoaffinity purification method to isolate endogenous mGluR2-containing assemblies from mouse brain and visualize them via cryo-EM. Analysis of the particle sets reveals the molecular structures of at least 11 distinct endogenous receptor assemblies that span active and inactive states, homomeric and heteromeric dimers, and G protein-coupled and uncoupled species. We find that mGluR2 homodimers and mGluR2/3 heterodimers are the major endogenous mGluR2-containing species present in the brain, with the mGluR2/3 heterodimers detected only in active state complexes, potentially reflecting basal activation of mGluR3 containing dimers by chloride. Reconstructing a comprehensive conformational equilibrium for the brain-isolated receptors in detergent reveals endogenous ternary complexes comprising mGluR2 homodimers and mGluR2/3 heterodimers with a single GoA heterotrimer which exhibit significant differences from prior studies with recombinant systems. Our work illuminates the endogenous conformational, proteomic and compositional landscape of the heterogenous mGluR2 complexes in the brain, thereby providing a structural framework for the pathophysiology of psychiatric disorders. This information has the potential to be leveraged for therapeutic targeting of endogenous glutamatergic signaling complexes.

neuroscience↗

bioRxiv2026

PFOA induced metabolic and immune perturbations in a SARS-2 infection model

This study evaluates the impact of PFOA exposure on the metabolome and immune response to SARS-2 using a ferret model. Ferrets were separated into control or PFOA-exposed groups (10/mg/kg/day) and challenged with SARS-2. Longitudinal analyses encompassing clinical assessments, serological profiling, histopathology, and untargeted nuclear magnetic resonance (NMR) metabolomics revealed significant metabolic and immunological perturbations. We found prominent effects of PFOA exposure on metabolism, which resulted in altered metabolic responses to SARS-2 infection. PFOA exposure was also associated with impaired immune function, as evidenced by decreased serum IgG levels, increased viral loads, and prolonged peak infectivity. These findings underscore the consequences of PFOA exposure on host metabolism and immunity during infectious diseases.

pharmacology and toxicology↗

bioRxiv2026

The selectivity implications of docking libraries with greater and lesser similarities to bio-like molecules

As virtual libraries have expanded into the tens of billions via make-on-demand chemistry, their similarity to metabolites, natural products, and drugs ("bio-like" molecules) has rapidly diminished. Despite this divergence, molecular docking of these ultra-large libraries has yielded molecules at higher experimental hit-rates and with improved affinities. The structural divergence from bio-like space raises the possibility that molecules from these ultra-large libraries have improved selectivity. Just as plausibly, if hit-rates on-target are divorced from similarity to bio-like molecules, so too may be selectivity against off-targets. Here, we test whether docking hits for the 5-HT2A serotonin receptor from ultra-large libraries are more selective than those from smaller and more bio-like "in-stock" libraries. Chemoinformatic similarity predicts that docking actives from the in-stock library have more off-targets than the more chemically novel hits emerging from docking the ultra-large library. This may reflect the bias of the known, however, as when tested experimentally at scale against 318 GPCRs, both 16 agonists from the ultra-large library and 20 actives from the in-stock library had similar numbers of off-targets. While the ultra-large library hits are more sub-type selective for the 5-HT2A over the 5-HT2B and 5-HT2C receptors, overall these results may suggest that selectivity against off-targets, like affinity and hit-rates for on-targets, is divorced from library similarity to bio-like molecules.

biophysics↗

bioRxiv2025

Pharmacological activation of AMPK rescues mitophagy defects in models of FBXL4-related mitochondrial DNA depletion syndrome

Distinct mitophagy pathways can eliminate not only damaged mitochondria but also healthy ones. In Mitochondrial DNA Depletion Syndrome 13 (MTDPS13), dysregulated BNIP3/NIX-driven mitophagy of functional mitochondria is thought to be the key pathological driver. Patient mutations in the E3 ubiquitin ligase FBXL4 impair the proteasomal degradation of the mitophagy receptors BNIP3 and NIX, causing their accumulation and excessive mitophagy. As a result, mitochondrial content and oxidative phosphorylation decline sharply across multiple tissues, leading to early mortality, with no effective treatments currently existing. In this study, we demonstrate that activating AMPK markedly suppresses BNIP3/NIX-dependent mitophagy and restores mitochondrial respiration in FBXL4-deficient cells. Using both fibroblasts derived from MTDPS13 patients and a chemically-induced in vivo model, we show that small molecule AMPK activation inhibits BNIP3/NIX-mediated mitophagy and recovers mitochondrial content. This work therefore highlights the therapeutic potential of targeting AMPK in MTDPS13.

cell biology↗

bioRxiv2025

The polypharmacological profiles of xanomeline and N-desmethylxanomeline

The muscarinic agonist xanomeline in combination with the peripherally restricted muscarinic antagonist trospium has recently been approved for treatment of schizophrenia. Xanomeline represents the first approved antipsychotic drug without apparent activity at D2-dopamine receptors. In humans, xanomeline is reported to be metabolized to N-desmethylxanomeline, which has a similar pharmacokinetic profile to xanomeline, although its pharmacology has not been reported. We discovered that xanomeline and N-desmethylxanomeline have potent agonist and antagonist actions at many biogenic amine G protein coupled receptors. These results suggest that at least some of the actions of xanomeline and N-desmethylxanomeline could be mediated by off-target actions at serotonergic, dopaminergic, histaminergic, adrenergic and other receptors. We discuss the potential implications of these findings.

neuroscience↗

bioRxiv2025

Common and distinct roles of AMPKγ isoforms in small-molecule activator-stimulated glucose uptake in mouse skeletal muscle

ObjectiveSmall-molecule activators targeting the allosteric drug and metabolite (ADaM) site of AMPK enhance insulin-independent glucose uptake in skeletal muscle and lower glucose in preclinical models of hyperglycemia. The regulatory AMPK{gamma} subunit plays a central role in energy sensing. While the skeletal muscle-selective {gamma}3 isoform is essential for AMP/ZMP-induced glucose uptake, it is dispensable for ADaM site-binding activators. We hypothesized that the predominant {gamma}1 isoform is required for ADaM site activator-stimulated glucose uptake in skeletal muscle. MethodsSingle-nucleus RNA sequencing (snRNA-seq) was performed on mouse and human skeletal muscle mapping AMPK subunit isoform distribution across resident cell types. To determine {gamma} isoform-specific requirements for activator-stimulated glucose uptake, skeletal muscle-specific inducible AMPK{gamma}1/{gamma}3 double knockout (im{gamma}1-/-/{gamma}3-/-) and single knockout (im{gamma}1-/- and im{gamma}3-/-) mice were generated. Ex vivo glucose uptake was measured following treatment with AICAR (AMP-mimetic) or MK-8722 (ADaM site activator), and in vivo MK-8722-induced blood glucose lowering was assessed. ResultssnRNA-seq revealed distinct AMPK isoform distribution: {gamma}1 was ubiquitously expressed, whereas {gamma}3 was enriched in glycolytic myofibers in both mouse and human skeletal muscle. Ex vivo, glucose uptake stimulated by either AICAR or MK-8722 was abolished in im{gamma}1-/-/{gamma}3-/- muscle, and MK-8722-induced blood glucose lowering was significantly blunted in vivo. AICAR but not MK-8722-stimulated muscle glucose uptake was abolished in im{gamma}3-/-, whereas both activators fully retained effects on glucose uptake and glucose lowering in im{gamma}1-/- mice. ConclusionsWhile {gamma}1 predominates in stabilizing the AMPK2{beta}2{gamma}1 complex, it is dispensable for AMPK activator-stimulated glucose uptake in skeletal muscle, whether mediated via the nucleotide-binding or ADaM site.

biochemistry↗

bioRxiv2025

SARS-CoV-2 causes chronic lung inflammation and impaired respiratory capacity in aged Roborovski dwarf hamsters

Roborovski dwarf hamsters are permissive for SARS-CoV-2 infection and progress to acute viral pneumonia with profound lung tissue injury, recapitulating hallmarks of severe COVID-19 in vulnerable patient groups such as older adults. In this study, we established dwarf hamster whole body plethysmography and assessed disease severity and propensity for long-term compromise of lung recovery from severe COVID-19-like disease in young, adult, and aged animals. Aged dwarf hamsters infected intranasally with variant of concern (VOC) omicron BA.4 experienced more severe clinical signs, carried a higher lung virus load, and had a greater risk of succumbing to infection. Resting airway hypersensitivity was transiently increased in aged, but not young, dwarf hamsters 3-4 days post infection (dpi). Pharmacologically induced respiratory distress revealed compromised lung capacity in animals of both age groups at peak disease. Aged animals showed impaired respiratory function for 45 days, mounted a weaker antiviral response, and developed chronic pneumonia with lasting tissue damage. Treatment of acute disease with approved antivirals, paxlovid-like nirmatrelvir+ritonavir or molnupiravir, prevented long-term respiratory sequelae in aged animals. Nirmatrelvir+ritonavir fully suppressed transient respiratory distress and mediated complete survival of aged animals. This study shows a high positive correlation between host age and SARS-CoV-2 disease severity in dwarf hamsters, establishes a model for chronic pneumonia with impaired respiratory capacity in at-risk hosts, and demonstrates benefit of antiviral therapy of acute disease for long-term respiratory health. Author SummaryIn the COVID-19 pandemic, the frequency of chronic respiratory insufficiency after acute SARS-CoV-2 infection was positively linked to patient age. Roborovski dwarf hamsters recapitulate hallmarks of life-threatening COVID-19 in at-risk patients that present with acute respiratory failure and prolonged respiratory incapacitation. In this study, we monitored disease progression and lung function in young and aged dwarf hamsters infected with a VOC omicron isolate and assessed the effect of antiviral treatment on long-term lung function. We established a strong correlation between host age and SARS-CoV-2 disease severity in dwarf hamsters, identified a high propensity of aged animals to develop chronic lung inflammation, and demonstrated a long-term loss of respiratory capacity in the subset of aged animals that survived the acute infection. Antiviral treatment suppressed the development of late sequelae and preserved lung function. These results have important implications for effective SARS-CoV-2 management in aged hosts at high risk of developing severe viral pneumonia with long-term impaired lung function.

microbiology↗

bioRxiv2025

Mechanism and cellular actions of the potent AMPK inhibitor BAY-3827

Inhibition of AMP-activated protein kinase (AMPK) is under increasing investigation for its therapeutic potential in many diseases, including certain cancers. However, existing AMPK- inhibitors available as tool compounds are largely limited to compound C/dorsomorphin and SBI-0206965, both of which suffer from poor selectivity and off-target effects. Here we describe the structure-based molecular insights and cellular actions of a recently identified potent AMPK inhibitor, BAY-3827. Kinase selectivity profiling and sequence analyses of kinases that are highly or weakly inhibited by BAY-3827 uncovered key conserved residues involved in its inhibitory mechanism. A 2.5 [A] co-crystal structure of the AMPK kinase domain (KD)-BAY-3827 complex and comparison with known KD-inhibitor structures, revealed an overlapping site in the ATP-binding pocket and an C helix-out conformation. A distinct feature of the BAY-3827-bound state is the formation of a disulfide bridge between the D helix Cys106 and the activation loop residue Cys174. This bridge appears to stabilize the activation loop such that Asn162 repositions the DFG motif Phe158 toward the C-terminal kinase lobe, displacing His137 and disrupting the regulatory spine, thereby promoting an inactive state. In hepatocytes, 2.5-5 M BAY-3827, but not the structurally resembling inactive BAY-974, fully blocked AMPK activator (MK-8722)-mediated phosphorylation of ACC1 and corresponding inhibition of lipogenesis. Unbiased transcriptome analysis in MK- 8722-treated wild-type and AMPK-null hepatocytes revealed that 5 M BAY-3827 downregulated >30% of MK-8722-stimulated AMPK-dependent genes. Based on its greater selectivity and potency substantiated by comprehensive structural and cellular investigations, BAY-3827 is a powerful tool to delineate AMPK functions. One-sentence summaryWe provide the mechanism of action of the potent and selective AMPK inhibitor BAY-3827, which blocks AMPK-dependent cellular functions.

biochemistry↗

bioRxiv2024

Diversity of set-related neuronal activity in the dorsal premotor cortex of monkeys during a path-planning task

Actions involve multiple levels. The dorsal premotor area (PMd) of the primate cerebral cortex is involved in the preparation of actions based on perceptual information. In this study, we recorded neuronal activity from the PMd of monkeys while they performed a path-finding task. In the task, the animals were required to move a cursor step by step to a goal in a maze-like display, and the arm movement and the direction of the cursor operation were dissociated. We observed neurons involved in the preparation of a single arm movement and neurons involved in the preparation of a single cursor operation. Cursor operation-related neurons were also obtained from the lateral prefrontal cortex (lPFC), but the PMd neurons showed more preparatory properties during the execution period than the lPFC neurons. Furthermore, we found neurons involved in the preparation of a specific sequence of cursor movements. The PMd included not only all types of single-shot preparatory neurons but also preparatory neurons for a variety of complex sequences for arm movements and cursor manipulation. These results suggest that the PMd contains diverse neurons involved in different levels of action preparation. Such diversity is one of the critical neural bases for robust goal-directed behavior in complex environments. SignificanceThere are different levels in actions. The dorsal premotor cortex (PMd) is involved in the preparation of actions based on perceptual information. Here, we recorded neuronal activity from the PM d of monkeys while performing a path-finding task, i.e., moving a cursor step by step to a goal in a maze-like display. In addition to neurons involved in the preparation of a single arm movement and neurons involved in the preparation of a single cursor operation, cells involved in the preparation of a specific sequence of cursor movements were observed. These results suggest that the PMd contains diverse neurons involved in different levels of action preparation. Such diversity is one of the critical neural bases for robust goal-directed behavior in complex environments.

neuroscience↗

bioRxiv2024

M1-linked Ubiquitination by LUBAC Regulates AMPK Activity and the Response to Energetic Stress

Methionine-1 (M1)-linked ubiquitin chains, assembled by the ubiquitin ligase LUBAC and cleaved by the deubiquitinase OTULIN, are critical regulators of inflammation and immune homeostasis. Genetic loss of either LUBAC or OTULIN causes autoinflammatory syndromes, which are associated with defects in glycogen and lipid metabolism. However, how LUBAC and OTULIN regulate metabolic signalling remains unknown. Here, we demonstrate that LUBAC promotes, while OTULIN restricts, activation of the key metabolic regulator AMP-activated protein kinase (AMPK) in cells, mice, and human samples. LUBAC and OTULIN interact with AMPK, control its M1-ubiquitination, and regulate its activation in response to glucose starvation and allosteric activation. During starvation, LUBAC deficiency impairs autophagy induction and hinders the shift from oxidative phosphorylation to glycolysis. Strikingly, LUBAC-deficient Drosophila have a strongly reduced survival rate after starvation. Our work identifies LUBAC and OTULIN as physiological regulators of AMPK, providing the first mechanism by which M1-linked ubiquitin chains regulate metabolic signalling.

cell biology↗

bioRxiv2024

AMPK activation promotes transcriptional activation of TFEB through its dephosphorylation

Transcription Factor EB (TFEB) is a critical regulator of lysosomal biogenesis, autophagy and energy homeostasis through controlling expression of genes belonging to the coordinated lysosomal expression and regulation network. AMP-activated protein kinase (AMPK) has been reported to phosphorylate TFEB at three conserved C-terminal serine residues (S466, S467, S469) and these phosphorylation events were essential for transcriptional activation of TFEB. In sharp contrast to this proposition, here we demonstrate that AMPK activation leads to dephosphorylation of the C-terminal sites, and that AMPK is dispensable for mTORC1-mediated/torin1-sensitive TFEB activation. We show that a synthetic peptide encompassing C-terminal serine residues of TFEB is a poor substrate of AMPK. Treatment of cells with AMPK activator (MK-8722) or mTOR inhibitor (torin1) robustly dephosphorylated TFEB not only at mTORC1-targeted N-terminal serine sites, but also at the C-terminal sites. Loss of function of AMPK abrogated MK-8722-but not torin1-induced dephosphorylation and induction of the vast majority of TFEB target genes.

biochemistry↗

bioRxiv2024

Protocol for muscle fiber type and cross-sectional areaanalysis in cryosections of whole lower mouse hindlimbs

We outline a robust, simple, and cost-effective method to simultaneously visualize all mouse lower hindlimb skeletal muscles. We describe procedures for orientating the whole lower hindlimb in gum tragacanth prior to freezing, simplifying the proceeding experimental steps, and enhancing the clarity and comprehensiveness of characterizations. We then detail steps for quantifying muscle fiber size and fiber type characteristics in a single cryosection using immunofluorescence and histochemistry. This protocol can be applicable for commonly used histological and (immuno) histochemical evaluations such muscle degeneration/regeneration, fibrosis, immune cell infiltration, enzymatic activity and glycogen content. HighlightsO_LIEmbedding and orientating mouse lower hindlimb in tragacanth before freezing enhances clarity and simplifies steps. C_LIO_LISimultaneously visualizing myofibers in different muscle compartments enables efficient and comprehensive evaluations of morphology and physiological characteristics. C_LIO_LISingle cryosection analysis of myofiber size and types with immunofluorescence. C_LIO_LIApplicable for evaluating muscle degeneration, fibrosis, and immune infiltration. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=194 SRC="FIGDIR/small/608909v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@9d3fe4org.highwire.dtl.DTLVardef@1cdcc85org.highwire.dtl.DTLVardef@2e494eorg.highwire.dtl.DTLVardef@cebfc6_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2024

Information structure of heterogeneous criticality in fish school

The integrated information theory (IIT) measures the degree of consciousness in living organisms from an information-theoretic perspective. This theory can be extended to general systems such as those measuring criticality. Herein, we applied the IIT to actual collective behaviour (Plecoglossus altivelis). We found that the group integrity (i.e., {Phi}) could be maximised in the critical state and that several levels of criticalities existed in a group as subgroups. Furthermore, these fragmented critical groups coexisted with traditional criticality as a whole. The distribution of high-criticality subgroups was heterogeneous in terms of time and space. In particular, the core fish in the high-criticality group tended to be unaffected by internal and external stimulation, in contrast to those in the low-criticality group. The results of this study are consistent with previous interpretations of critical phenomena and provide a new interpretation of the detailed dynamics of an empirical critical state.

animal behavior and cognition↗

bioRxiv2024

Personalized Molecular Signatures of Insulin Resistance and Type 2 Diabetes

HighlightsO_LIAdvanced proteomics analysis reveals personalized signatures of insulin resistance C_LIO_LIFasting muscle proteome and phosphoproteome predicts whole-body insulin sensitivity C_LIO_LIInsulin-stimulated phosphoproteome reveals selective insulin resistance signatures C_LIO_LIPhosphoproteome and proteome atlas explains sex-specific muscle metabolism C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/578994v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@a83000org.highwire.dtl.DTLVardef@1e77336org.highwire.dtl.DTLVardef@3d1ecdorg.highwire.dtl.DTLVardef@b1592b_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG Insulin resistance is a hallmark of type 2 diabetes, which is a highly heterogeneous disease with diverse pathology. Understanding the molecular signatures of insulin resistance and its association with individual phenotypic traits is crucial for advancing precision medicine in type 2 diabetes. Utilizing cutting-edge proteomics technology, we mapped the proteome and phosphoproteome of skeletal muscle from >120 men and women with normal glucose tolerance or type 2 diabetes, with varying degrees of insulin sensitivity. Leveraging deep in vivo phenotyping, we reveal that fasting proteome and phosphoproteome signatures strongly predict insulin sensitivity. Furthermore, the insulin-stimulated phosphoproteome revealed both dysregulated and preserved signaling nodes - even in individuals with severe insulin resistance. While substantial sex-specific differences in the proteome and phosphoproteome were identified, molecular signatures of insulin resistance remained largely similar between men and women. These findings underscore the need for precision medicine approaches in type 2 diabetes care, acknowledging disease heterogeneity.

biochemistry↗

bioRxiv2023

Single-cell Glycogenomics Deciphers Links Between Altered Transcriptional Regulation and Aberrant Glycosylation in Alzheimer's Disease

Glycosylation is increasingly recognized as a potential therapeutic target in Alzheimers disease. In recent years, evidence of Alzheimers disease-specific glycoproteins has been established. However, the mechanisms underlying their dysregulation, including tissue- and cell-type specificity, are not fully understood. We aimed to explore the upstream regulators of aberrant glycosylation by integrating multiple data sources using a glycogenomics approach. We identified dysregulation of the glycosyltransferase PLOD3 in oligodendrocytes as an upstream regulator of cerebral vessels and found that it is involved in COL4A5 synthesis, which is strongly correlated with amyloid fiber formation. Furthermore, COL4A5 has been suggested to interact with astrocytes via extracellular matrix receptors as a ligand. This study suggests directions for new therapeutic strategies for Alzheimers disease targeting glycosyltransferases. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/573290v2_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@14d608forg.highwire.dtl.DTLVardef@fe8352org.highwire.dtl.DTLVardef@15f8f77org.highwire.dtl.DTLVardef@c3ef28_HPS_FORMAT_FIGEXP M_FIG C_FIG

systems biology↗