The shikimate pathway in Saccharomyces cerevisiae is pivotal for the biosynthesis of aromatic amino acids, which are essential for protein synthesis and cellular homeostasis. Here, we investigated the regulatory mechanisms within this pathway, focusing on the two key enzymes: phospho-2-dehydro-3-deoxyheptonate aldolase, tyrosine-inhibited (Aro4) and phospho-2-dehydro-3-deoxyheptonate aldolase, phenylalanine-inhibited (Aro3). Deletion of either the ARO4 or ARO3 genes led to significant intracellular accumulation of phenylalanine or tyrosine, respectively, upon feeding with the corresponding metabolite. Remarkably, we discovered that this metabolite accumulation promotes the formation of amyloid-like assemblies within cells, as evidenced by amyloid-specific staining and antibody recognition towards phenylalanine and tyrosine assemblies. These assemblies strongly correlated with reduced cell viability. Treatment with common amyloid inhibitors significantly mitigated the formation of these toxic assemblies, improving cell growth, and viability in the mutant strains. Additionally, although overexpression of ARO3 in the aro4Δ background partially rescued the growth phenotype, combining ARO3 overexpression with trimethylamine N-oxide (TMAO) treatment provided an additive growth rescue effect. Our findings highlight the role of cellular self-assembly in regulating the shikimate pathway and reveal a previously unknown link between metabolic dysregulation and the formation of toxic amyloid-like structures. This discovery offers new insights into inherited metabolic disorders and potential therapeutic approaches.

Human cytomegalovirus (HCMV) establishes lifelong latency, during which immediate-early (IE) gene expression is strongly repressed. IE1 and IE2 are considered master regulators of the lytic cycle, yet it remains unclear whether their expression levels are sufficient to determine infection outcome, defined here as the balance between lytic and latent infection, and which viral or cellular processes underpin this control. Here, we show that when viral entry is enhanced in monocytes, overexpression of either IE1 or IE2 significantly increases lytic replication, identifying their abundance as a critical barrier governing infection outcome. Mechanistic analysis reveals that these effects of IE1 and IE2 are mainly mediated through two distinct modes of host manipulation. IE1 promotes disruption of PML bodies, thereby facilitating a broad increase of viral gene expression, whereas IE2 elevates cellular dNTP pools and creates an environment permissive for viral DNA replication, consistent with two key limiting barriers to the initiation of lytic replication. Notably, induction of IE1 in latently infected cells is also sufficient to promote reactivation of viral gene expression. Together, these findings define the limiting functions of IE1 and IE2 in overcoming host-imposed barriers to lytic replication and reactivation.

Crystal engineering offers a route to functional molecular solids through controlled noncovalent interactions. In centrosymmetric crystals, piezoelectricity can be induced by stereoselective doping, where chiral additives are incorporated in a biased orientation that lowers inversion symmetry and generates net polarization. However, the microscopic origin of this polarization, specifically whether it arises primarily from dipole mismatch between the dopant and the host molecule it replaces, or from dopant-induced lattice distortion, remains generally unclear. Here, we disentangle these two contributions by incorporating four chiral N-acetyl-L-amino acids into the centrosymmetric crystal N-acetyl-DL-valine and examining the resulting materials using piezoelectric measurements, density functional theory (DFT), and low-frequency Raman spectroscopy that reveals concentration-dependent symmetry-breaking phenomena not resolved by conventional X-ray diffraction. We show that in the systems studied, macroscopic piezoelectricity correlates directly with the magnitude and orientation of local lattice distortions, whereas dipole mismatch along the polar axis plays a secondary role. These results establish a direct structure-function relation in doped molecular crystals and provide predictive design principles for engineering electromechanical response in molecular crystals through biased local distortions.

Ferrielectrics, materials with partly switchable polarization, enable functional responses such as pyroelectricity and piezoelectricity. However, purely organic examples and general design strategies remain scarce. Here we show that quasiracemates (QR), derived from enantiopolar centrosymmetric racemates, provide a generalizable route to organic ferrielectrics. In these structures, quasi-enantiomers assemble into antiparallel polar ribbons that reveal the hidden polarization of the parent racemate. When one quasi-enantiomer bears acidic protons capable of forming hydrogen bonds, a bistable double-well potential may emerges, enabling ferrielectric switching. Guided by this principle, we design ferrielectric QR composed of N-Ac-R-Val and N-Ac-S-Thr (P21). The crystals display ferrielectricity along with a large pyroelectric coefficient around 4*10^-9 (C/(K*cm^2) and a modest piezoelectric response (d22 around 2.75pm/V). The macroscopic polarization and polar properties are tunable by varying the N-Ac-S-Thr concentration.

Alzheimer's disease (AD) is characterized by a prolonged asymptomatic phase before cognitive decline emerges, yet the mechanisms driving symptom onset remain unclear. Here, we hypothesized that the transition from asymptomatic to symptomatic disease is linked to dysfunction of brain-immune communication. Retrograde neuronal tracing in the 5xFAD mouse model of amyloidosis reveals reduced brain-spleen connectivity at advanced disease stages. To probe the functional role of the brain-spleen axis in coping with disease, we denervated the splenic nerve at an early presymptomatic stage. This intervention accelerated cognitive decline, impaired splenic hematopoiesis, diminished monocyte recruitment to the brain, disrupted monocyte-microglia signaling networks, and reduced the transition of microglia from a homeostatic to a disease-associated (DAM) state. Conversely, enhancing splenic noradrenergic input increased hematopoiesis, restored monocyte homing to the brain, and delayed cognitive impairment. The protective role of splenic monocytes was independently validated in a retinal cytotoxic injury model, in which splenic denervation impairs post-insult survival of retinal ganglion cells. Together, these findings identify an active brain-spleen circuit in regulating monocyte recruitment, and establish peripheral monocytes as important drivers of microglial state transitions and disease progression.

Abstract Cells maintain metabolite homeostasis (metabolostasis) by buffering fluctuations in metabolite levels, yet the limits of this buffering and the mechanisms underlying metabolic toxicity remain poorly understood. To study this, we systematically overfed metabolites in Saccharomyces cerevisiae and quantified associations with growth inhibition, intracellular aggregation, and multiomic perturbations. We identify metabolite-specific failure thresholds at which amyloid-like aggregates are observed, with graded growth inhibition detectable at sub-threshold concentrations, suggesting toxicity mechanisms beyond transporter saturation. Metabolites with higher network influence and broader pathway participation are associated with higher failure thresholds and smaller pathway disturbances. These patterns are associated with chemical properties and solubility: more soluble metabolites, while broadly tolerated, are associated with localised aggregates at their failure thresholds, whereas less soluble metabolites are associated with larger systemic pathway disruptions. Multiomic integration identifies a two-tiered translational regulatory architecture characterising cellular resilience to metabolic overfeeding. General resilience is associated with transcriptional commitment to resource conservation via attenuation of anabolic pathways. Metabolite-specific defense is characterised by high-magnitude translational regulatory events; for example, engagement of aromatic catabolism under phenylalanine overfeeding and energetic control pathways under glycine overfeeding. Together, our results operationally define metabolostasis as a cellular system associated with constraint of metabolite concentrations, coordination of network and pathway-level regulation, and buffering against amyloid-like aggregation, highlighting how network topology, pathway architecture, and chemical properties are associated with metabolic resilience and toxicity thresholds.

Non-canonical metabolic functions of signaling molecules contribute to cancer plasticity and metastatic progression. Here, we demonstrated that PDE5a inhibitors, including sildenafil (Viagra), induced lysosomal cholesterol accumulation across multiple mouse and human cancer models, reducing cholesterol bioavailability and impairing cancer cell migration and metastasis. Cancer cells exhibited heightened sensitivity due to reduced lysosomal gene expression, rendering them particularly vulnerable to disrupted cholesterol trafficking. Mechanistically, elevated cGMP bound the lysosomal cholesterol transporter NPC1, impairing cholesterol export and phenocopying Niemann-Pick type C pathology. The resulting cholesterol depletion disrupted membrane lipid rafts and mitochondrial bioenergetics, thereby limiting metastatic capacity and triggering compensatory SREBP2 activation with increased cholesterol synthesis. Combining sildenafil with statins yields additive antimetastatic effects by concurrently blocking lysosomal cholesterol export and cholesterol biosynthesis. Consistently, analysis of digital health records demonstrated significantly improved survival among sildenafil users, with a dose-dependent additive benefit observed when combined with statins. Together, these findings identify increasing cGMP levels through PDE5a inhibition as a potential strategy to restrict metastasis and offer a potential mechanistic basis for the beneficial effects of sildenafil.

Cancer-associated cachexia (CAC) is a multifactorial and currently incurable syndrome responsible for nearly one-third of cancer-related deaths. It contributes to therapy resistance and increases mortality among affected patients. In this study, we show that cancer-induced systemic inflammation alters vagal tone in CAC mouse models. This vagal dysregulation disrupts the brain-liver vagal axis, leading to a reprogramming of hepatic protein metabolism through the depletion of HNF4α, a key transcriptional regulator of liver function. The loss of HNF4α disrupts hepatic metabolism and promotes systemic inflammation, resulting in cachectic phenotypes. Interventions targeting the right cervical vagus nerve surgically, chemically, electrically, or through a non-invasive transcutaneous device attenuate CAC progression, alleviate its clinical manifestations, and synergize with chemotherapy to improve overall health and survival in mice.

PURPOSE. This study aims to elucidate on changes in biological pathways in rabbit corneas induced by two methods of light-activated corneal stiffening: topical application of riboflavin with dextran (RF-D) or WST11 with dextran (WST-D) followed by ultraviolet A (UVA) or near-infrared (NIR) illumination, respectively. METHODS. Rabbit corneas were mechanically de-epithelialized, then left untreated (N = 3) or treated with either RF-D/UVA (N = 3) or WST-D/NIR (N = 3). After one week, quantitative proteomics was performed on untreated, RF-D/UVA- and WST-D/NIR-treated corneas. Pathway enrichment analysis was performed to identify the biological processes associated with the treatments. To identify the abundance and spatial distribution of lipids in the untreated, WST-D/NIR- and RF-D/UVA-treated corneal stroma, lipid mass spectrometry imaging was performed together with hematoxylin and eosin staining. R ESULTS. Between RF-D/UVA- and WST-D/NIR-treated corneas, 37 and 39 proteins, respectively, were differentially expressed compared to untreated corneas (P < 0.05). Pathway enrichment analysis showed the effect of RF-D/UVA treatment on cell metabolism and terminal differentiation of keratocytes, while WST-D/NIR modified extracellular matrix regulation and the mitogen-activated protein kinase signaling cascade. When comparing the RF-D/UVA and WST-D/NIR treatment, 74 proteins were differentially expressed, affecting cellular metabolism and respiration, complement activation, the activation of matrix metalloproteinases, and lipoprotein metabolism. The lipid profile for the RF-D/UVA- and WST-D/NIR-treated stromas were similar, whereas differences were observed comparing both treatments to untreated corneal stroma. CONCLUSIONS. Proteomics indicated a metabolic shift from oxidative phosphorylation to glycolysis and hypoxia after RF-D/UVA treatment. In contrast, WST-D/NIR stiffening maintained normal respiration and involved extracellular matrix remodeling.

AS1411 is a G-rich DNA aptamer that targets the multifunctional RNA-binding protein nucleolin. AS1411 has both antiproliferative and cell size-regulating activities and has been evaluated for clinical utility, reaching phase II trials as an anticancer agent. The mechanisms underlying cell size effects of AS1411 are not well understood and broad characterization of its molecular effects is lacking. Here, we used a multi-omics approach to profile transcriptome, proteome and lipidome changes in AS1411-treated NIH-3T3 cells, which increase in size in response to the aptamer. We found that AS1411 caused downregulation of cholesterol biosynthesis pathway enzymes at both mRNA and protein levels, without an accompanying reduction in cellular cholesterol levels or cholesterol uptake. In addition, AS1411 induced changes in several lipid classes, including increases in phosphatidylethanolamine levels. Ratiometric imaging of Di-4-ANEPPS-labeled cells showed that AS1411 decreases the fluidity of intracellular membranes. Thus, aptamer engagement of nucleolin affects lipid biosynthesis and homeostasis, likely contributing to its roles in cell size control.

Malignant gliomas are heterogeneous tumors, mostly incurable, arising in the central nervous system (CNS) driven by genetic, epigenetic, and metabolic aberrations. Mutations in isocitrate dehydrogenase (IDH1/2mut) enzymes are predominantly found in low-grade gliomas and secondary high-grade gliomas, with IDH1 mutations being more prevalent. Mutant-IDH1/2 confers a gain-of-function activity that favors the conversion of a-ketoglutarate (α-KG) to the oncometabolite 2-hydroxyglutarate (2-HG), resulting in an aberrant hypermethylation phenotype. Yet, the complete depiction of the epigenetic alterations in IDHmut cells has not been thoroughly explored. Here, we applied an unbiased approach, leveraging epigenetic-focused cytometry by time-of-flight (CyTOF) analysis, to systematically profile the effect of mutant-IDH1 expression on a broad panel of histone modifications at single-cell resolution. This analysis revealed extensive remodeling of chromatin patterns by mutant-IDH1, with the most prominent being deregulation of histone acetylation marks. The loss of histone acetylation occurs rapidly following mutant-IDH1 induction and affects acetylation patterns over enhancers and intergenic regions. Notably, the changes in acetylation are not predominantly driven by 2-HG, can be rescued by pharmacological inhibition of mutant-IDH1, and reversed by acetate supplementations. Furthermore, cells expressing mutant-IDH1 show higher epigenetic and transcriptional heterogeneity and upregulation of oncogenes such as KRAS and MYC, highlighting its tumorigenic potential. Our study underscores the tight interaction between chromatin and metabolism dysregulation in glioma and highlights epigenetic and oncogenic pathways affected by mutant-IDH1-driven metabolic rewiring.

Mitochondrial carrier homolog 2 (MTCH2) is a regulator of apoptosis, mitochondrial dynamics, and metabolism. Loss of MTCH2 results in mitochondrial fragmentation, an increase in whole-body energy utilization, and protection against diet-induced obesity. In this study, we used temporal metabolomics on HeLa cells to show that MTCH2 deletion results in a high ATP demand, an oxidized cellular environment, and elevated utilization of lipids, amino acids, and carbohydrates, accompanied by a decrease in several metabolites. Lipidomics analysis revealed a strategic adaptive reduction in membrane lipids and an increase in storage lipids in MTCH2 knockout cells. Importantly, MTCH2 knockout cells showed an increase in mitochondrial oxidative function, which may explain the higher energy demand. Interestingly, this imbalance in energy metabolism and reductive potential triggered by MTCH2-deletion prevents NIH3T3L1 preadipocytes from differentiating into mature adipocytes, an energy consuming reductive biosynthetic process. In summary, the loss of MTCH2 leads to increased mitochondrial oxidative activity and energy demand, creating a catabolic and oxidative environment that fails to fuel the anabolic processes required for lipid accumulation and adipocyte differentiation.

Systemic metabolism ensures energy homeostasis through inter-organ crosstalk regulating thermogenic adipose tissue. Unlike the well-described inductive role of the sympathetic system, the inhibitory signal ensuring energy preservation remains poorly understood. Here, we show that, via the mechanosensor Piezo2, sensory neurons regulate morphological and physiological properties of brown and beige fat and prevent systemic hypermetabolism. Targeting runt-related transcription factor 3 (Runx3)/parvalbumin (PV) sensory neurons in independent genetic mouse models resulted in a systemic metabolic phenotype characterized by reduced body fat and increased insulin sensitivity and glucose tolerance. Deletion of Piezo2 in PV sensory neurons reproduced the phenotype, protected against high-fat-diet-induced obesity, and caused adipose tissue browning and beiging, likely driven by elevated norepinephrine levels. Finding that brown and beige fat are innervated by Runx3/PV sensory neurons expressing Piezo2 suggests a model in which mechanical signals, sensed by Piezo2 in sensory neurons, protect energy storage and prevent a systemic hypermetabolic phenotype.

Argininosuccinate synthetase 1 (ASS1) expression and arginine availability are key metabolic determinants that influence tumor fitness and regulate immune interactions within the tumor microenvironment (TME). Using an orthotopic triple-negative breast cancer (TNBC) model, we demonstrate that arginine deprivation heightens tumor dependence on the TME for survival. Mechanistically, fibroblasts sustain tumor viability by supplying arginine, whereas macrophages cooperate with stromal cues to activate Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling, thereby enhancing tumor survival. Concordantly, a JAK-STAT gene-expression signature correlates with ASS1 levels in human TNBC datasets. Translationally, combined pharmacological inhibition of JAK signaling with arginine deprivation markedly suppresses tumor growth. Together, these findings reveal a TME-driven, targetable stromal–immune circuit that enables tumors to withstand arginine deficiency-induced metabolic stress. Broadly, our work highlights that mapping and strategically inducing metabolic dependencies can reveal actionable compensatory pathways, offering opportunities to improve cancer therapy.

Brain metastasis (BM) carries a poor prognosis, yet the molecular basis of brain tropism remains unclear. Analysis of breast cancer BM (BCBM) revealed pervasive p53 inactivation through mutations and/or aneuploidy, with pathway disruption already present in primary tumors. Functionally, p53 inactivation markedly increased BCBM formation and growth in vivo, causally linking p53 perturbation to BM. Mechanistically, p53 inactivation upregulated SCD1 and fatty acid synthesis (FAS), essential for brain-metastasizing cells; SCD1 knockout abolished the p53-dependent growth advantage. Molecularly, p53 suppressed SCD1 directly through promoter binding and indirectly by downregulating its co-activator DEPDC1. Astrocytes further enhanced FAS by secreting factors that were metabolized in a p53-dependent manner, promoting tumor survival, proliferation and migration. Finally, p53-deficient tumors were sensitive to FAS inhibition ex vivo and in vivo. Thus, we identify p53 inactivation as a driver of BCBM, reveal p53-dependent and astrocyte-dependent FAS modulation and highlight FAS as a therapeutically targetable BCBM vulnerability.

Huntington’s disease (HD) is an incurable inherited disorder caused by a repeated expansion of glutamines in the huntingtin gene ( Htt ). The mutant protein causes neuronal degeneration leading to severe motor and psychological symptoms. Selective downregulation of the mutant Htt gene expression is considered the most promising therapeutic approach for HD. We report the identification of small molecule inhibitors of Spt5-Pol II, SPI-24 and SPI-77, which selectively lower mutant Htt mRNA and protein levels in HD cells. In the BACHD mouse model, their direct delivery to the striatum diminished mutant Htt levels, ameliorated mitochondrial dysfunction, restored BDNF expression, and improved motor and anxiety-like phenotypes. Pharmacokinetic studies revealed that these SPIs pass the blood-brain-barrier. Prolonged subcutaneous injection or oral administration to early-stage mice significantly delayed disease deterioration. SPI-24 long-term treatment had no side effects or global changes in gene expression. Thus, lowering mutant Htt levels by small molecules can be an effective therapeutic strategy for HD.

Background: Fetal growth restriction (FGR) is a pregnancy complication in which a newborn fails to achieve its growth potential, increasing the risk of perinatal morbidity and mortality. Chronic maternal gestational hypoxia, as well as placental insufficiency are associated with increased FGR incidence; however, the molecular mechanisms underlying FGR remain unknown. Methods: Pregnant mice were subjected to acute or chronic hypoxia (12.5% O2) resulting in reduced fetal weight. Placenta oxygen transport was assessed by blood oxygenation level dependent (BOLD) contrast magnetic resonance imaging (MRI). The placentae were analyzed via immunohistochemistry and in situ hybridization. Human placentae were selected from FGR and matched controls and analyzed by immunohistochemistry (IHC). Maternal and cord sera were analyzed by mass spectrometry. Results: We show that murine acute and chronic gestational hypoxia recapitulates FGR phenotype and affects placental structure and morphology. Gestational hypoxia decreased labyrinth area, increased the incidence of red blood cells (RBCs) in the labyrinth while expanding the placental spiral arteries (SpA) diameter. Hypoxic placentae exhibited higher hemoglobin-oxygen affinity compared to the control. Placental abundance of Bisphosphoglycerate mutase (BPGM) was upregulated in the syncytiotrophoblast and spiral artery trophoblast cells (SpA TGCs) in the murine gestational hypoxia groups compared to the control. Hif1α levels were higher in the acute hypoxia group compared to the control. In contrast, human FGR placentae exhibited reduced BPGM levels in the syncytiotrophoblast layer compared to placentae from healthy uncomplicated pregnancies. Levels of 2,3 BPG, the product of BPGM, were lower in cord serum of human FGR placentae compared to control. Polar expression of BPGM was found in both human and mouse placentae syncytiotrophoblast, with higher expression facing the maternal circulation. Moreover, in the murine SpA TGCs expression of BPGM was concentrated exclusively in the apical cell side, in direct proximity to the maternal circulation. Conclusions: This study suggests a possible involvement of placental BPGM in maternal-fetal oxygen transfer, and in the pathophysiology of FGR. Funding: This work was supported by the Weizmann Krenter Foundation and the Weizmann – Ichilov (Tel Aviv Sourasky Medical Center) Collaborative Grant in Biomedical Research, by the Minerva Foundation, by the ISF KillCorona grant 3777/19.

A strategy for pandemic preparedness is the development of antivirals against a wide set of viral targets with complementary mechanisms of action. SARS-CoV-2 nsp3-mac1 is a viral macrodomain with ADP-ribosylhydrolase activity, which counteracts host immune response. Targeting the virus' immunomodulatory functionality offers a differentiated strategy to inhibit SARS-CoV-2 compared to approved therapeutics, which target viral replication directly. Here we report a fragment-based lead generation campaign guided by computational approaches. We discover tool compounds which inhibit nsp3-mac1 activity at low nanomolar concentrations, and with responsive structure-activity relationships, high selectivity, and drug-like properties. Using our inhibitors, we show that inhibition of nsp3-mac1 increases ADP-ribosylation, but surprisingly does not translate to demonstrable antiviral activity in cell culture and iPSC-derived pneumocyte models. Further, no synergistic activity is observed in combination with interferon gamma, a main protease inhibitor, nor a papain-like protease inhibitor. Our results question the extent to which targeting modulation of innate immunity-driven ADP-ribosylation can influence SARS-CoV-2 replication. Moreover, these findings suggest that nsp3-mac1 might not be a suitable target for antiviral therapeutics development.

Contact-sites are specialized zones of proximity between two organelles, essential for organelle communication and coordination. The formation of contacts between the Endoplasmic Reticulum (ER), and other organelles, relies on a unique membrane environment enriched in sterols. However, how these sterol-rich domains are formed and maintained had not been understood. We found that the yeast membrane protein Yet3, the homolog of human BAP31, is localized to multiple ER contact sites. We show that Yet3 interacts with all the enzymes of the post-squalene ergosterol biosynthesis pathway and recruits them to create sterol-rich domains. Increasing sterol levels at ER contacts causes its depletion from the plasma membrane leading to a compensatory reaction and altered cell metabolism. Our data shows that Yet3 provides on-demand sterols at contacts thus shaping organellar structure and function. A molecular understanding of this protein's functions gives new insights into the role of BAP31 in development and pathology.

Bacterial communication, Quorum Sensing (QS), is a target against virulence and prevention of antibiotic-resistant infections. 16 derivatives of Piperlongumine (PL), an amide alkaloid from Piper longum L., were screened for QS inhibition. PL-18 had the best QSI activity. PL-18 inhibited the lasR-lasI, rhlR-rhlI, and pqs QS systems of Pseudomonas aeruginosa. Pl-18 inhibited pyocyanin and rhamnolipids that are QS-controlled virulence elements. Iron is an essential element for pathogenicity, biofilm formation and resilience in harsh environments, its uptake was inhibited by PL-18. Pl-18 significantly reduced the biofilm biovolume including in established biofilms. PL-18-coated silicon tubes significantly inhibited biofilm formation. The transcriptome study of treated P. aeruginosa showed that PL-18 indeed reduced the expression of QS and iron homeostasis related genes, and up regulated sulfur metabolism related genes. Altogether, PL-18 inhibits QS, virulence, iron uptake, and biofilm formation. Thus, PL-18 should be further developed against bacterial infection, antibiotic resistance, and biofilm formation.