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TRIM49 Deficiency Stabilizes a Galectin-3/EGR1 Transcriptional Complex That Drives Invasiveness of Gastric Adenocarcinoma.

UNLABELLED: Tissue invasion is an initiating step of the cancer metastatic cascade. Unraveling the mechanisms underlying intracellular signaling pathway rewiring that activates downstream transcriptional machinery to drive invasiveness could help identify improved strategies to prevent and treat metastasis. Through an unbiased genome-wide CRISPR screen in a mouse model of gastric adenocarcinoma (GAC), an E3 ubiquitin ligase, tripartite motif-containing protein 49 (TRIM49), was identified as a potent suppressor of cancer invasiveness. In two thirds of GAC, TRIM49 expression was downregulated in invading cancer cells, in which TRIM49 deficiency correlated with deeper tumor infiltration and lymph node metastasis and was indicative of shorter overall patient survival. In multiple orthotopic GAC mouse models, TRIM49-deficient cancer cells were highly infiltrative, leading to multiorgan metastasis. Mechanistically, galectin-3, a putative regulator of cancer invasion, was stabilized in TRIM49-deficient cancer, largely because of the failure to undergo TRIM49-mediated polyubiquitination and proteasomal degradation. Consequently, galectin-3 assembled a complex with EGR1, thereby regulating transcriptional activities of a proinvasive gene module. As the galectin-3/EGR1 complex acted as a key node relaying proinvasive signaling, its disruption using GB1107, an oral galectin-3 inhibitor, suppressed tissue infiltration and metastasis of patient-derived xenografts. Taken together, a proinvasive galectin-3/EGR1 transcriptional complex was exploited by TRIM49-deficient GAC to fuel tissue invasion, representing an Achilles' heel that is potentially targetable to prevent metastasis. SIGNIFICANCE: A proinvasion galectin-3/EGR1 transcriptional complex is a therapeutic vulnerability in the highly invasive TRIM49-deficient gastric adenocarcinoma, which can be disrupted by the oral galectin-3 inhibitor GB1107 to prevent cancer spreading.

Stomach Neoplasms

The Evolutionary Maintenance of Amino Acid Prototrophy in Escherichia coli.

Escherichia coli is a prototroph and can synthesize all twenty proteinogenic amino acids when required to grow in minimal medium. There are approximately sixty protein-coding genes individually essential for amino acid synthesis. This is a large mutational target for the accumulation of detrimental mutations. E. coli can rewire biosynthetic pathways in response to mutational damage, but the limits of this capacity are poorly understood. Here, to address evolutionary robustness, we asked whether and how the phenotypes of irreversible mutations causing auxotrophy could be suppressed or bypassed in the absence of horizontal gene transfer (HGT). Spontaneous suppressors could be selected for only ten of fifty-nine mutants tested (detection limit ∼7 × 10-11). Mechanisms of suppression included regional amplifications, mutations increasing gene or operon expression, mutations relaxing enzyme specificity, and mutations causing biochemical pathway diversions. Overall, the data show that spontaneous suppression of auxotrophy caused by an irreversible mutation is an evolutionary survival mechanism relevant only to a minority of the genes essential for amino acid synthesis. As a consequence, the essential genetic foundations for amino acid prototrophy are expected to be degraded over time by mutations (Muller's ratchet) and metabolic rewiring alone will be insufficient to counteract this effect. This implies that maintaining phenotypes, including prototrophy in E. coli, and potentially other bacterial species, is likely to be reliant on HGT of housekeeping genes to counteract the effects of inevitable mutational inactivation. Accordingly, chromosomal HGT in bacteria may be critical for survival across diverse environmental niches.

Escherichia coli

iSoMAs: Finding isoform expression and somatic mutation associations in human cancers.

Aberrant alternative splicing, prevalent in cancer, impacts various cancer hallmarks involving proliferation, angiogenesis, and invasion. Splicing disruption often results from somatic point mutations rewiring functional pathways to support cancer cell survival. We introduce iSoMAs (iSoform expression and somatic Mutation Association), an efficient computational pipeline leveraging principal component analysis technique, to explore how somatic mutations influence transcriptome-wide gene expression at the isoform level. Applying iSoMAs to 33 cancer types comprising 9,738 tumor samples in The Cancer Genome Atlas, we identified 908 somatically mutated genes significantly associated with altered isoform expression across three or more cancer types. Mutations linked to differential isoform expression occurred through both cis- and trans-acting mechanisms, involving well-known oncogenes/suppressor genes, RNA binding protein and splicing factor genes. With wet-lab experiments, we verified direct association between TP53 mutations and differential isoform expression in cell cycle genes. Additional iSoMAs genes have been validated in the literature with independent cohorts and/or methods. Despite the complexity of cancer, iSoMAs attains computational efficiency via dimension reduction strategy and reveals critical associations between regulatory factors and transcriptional landscapes.

Humans

Molecular mechanisms of neuroendocrine regulation of molting in the Chinese mitten crab (Eriocheir sinensis): A transcriptomic analysis based on eyestalk ablation model.

Molting disability severely restricts the sustainable aquaculture of the Chinese mitten crab, yet the neuroendocrine mechanisms coordinating physiological responses remain poorly understood. Using unilateral eyestalk ablation to remove the primary source of molt-inhibiting hormone (MIH), we performed time-resolved transcriptomic profiling of the thoracic ganglion at 24 h (early premolt) and 48 h (ecdysis) post-ablation. We identified 2825 differentially expressed genes and uncovered a biphasic molecular response. At 24 h, the thoracic ganglion activates pathways associated with neuromuscular adaptation, oxidative stress, and cardiac muscle contraction. Notably, the arachidonic acid metabolism pathway is selectively rewired: cytochrome P450 ω-hydroxylases (CYP2J2, CYP4V2) are upregulated, while competing branches (epoxide hydrolase, cyclooxygenase) are suppressed, promoting local synthesis of the potent vasoconstrictor 20-HETE within the thoracic ganglion. This enzymatic switch provides a mechanistic link between MIH withdrawal and the local generation of elevated hemolymph pressure required for molting. By 48 h, the transcriptional program shifts toward chitin-based extracellular matrix remodeling, glycosphingolipid biosynthesis, and synaptic reorganization. Collectively, our findings redefine the thoracic ganglion as an active neuroendocrine integrator that translates reduced MIH signaling into phased physiological outputs, revealing a "neuro-endocrine-hemolymph pressure" regulatory axis. This study provides novel molecular targets (e.g., CYP2J2, CHS1, UGCG) for mitigating molting disability in E. sinensis aquaculture.

Animals

Ontogeny and Vulnerabilities of Drug-Tolerant Persisters in HER2+ Breast Cancer.

UNLABELLED: Resistance to targeted therapies is an important clinical problem in HER2-positive (HER2+) breast cancer. "Drug-tolerant persisters" (DTP), a subpopulation of cancer cells that survive via reversible, nongenetic mechanisms, are implicated in resistance to tyrosine kinase inhibitors (TKI) in other malignancies, but DTPs following HER2 TKI exposure have not been well characterized. We found that HER2 TKIs evoke DTPs with a luminal-like or a mesenchymal-like transcriptome. Lentiviral barcoding/single-cell RNA sequencing reveals that HER2+ breast cancer cells cycle stochastically through a "pre-DTP" state, characterized by a G0-like expression signature and enriched for diapause and/or senescence genes. Trajectory analysis/cell sorting shows that pre-DTPs preferentially yield DTPs upon HER2 TKI exposure. Cells with similar transcriptomes are present in HER2+ breast tumors and are associated with poor TKI response. Finally, biochemical experiments indicate that luminal-like DTPs survive via estrogen receptor-dependent induction of SGK3, leading to rewiring of the PI3K/AKT/mTORC1 pathway to enable AKT-independent mTORC1 activation. SIGNIFICANCE: DTPs are implicated in resistance to anticancer therapies, but their ontogeny and vulnerabilities remain unclear. We find that HER2 TKI-DTPs emerge from stochastically arising primed cells ("pre-DTPs") that engage either of two distinct transcriptional programs upon TKI exposure. Our results provide new insights into DTP ontogeny and potential therapeutic vulnerabilities. This article is highlighted in the In This Issue feature, p. 873.

Breast Neoplasms

Hierarchical metabolic engineering for rewiring cellular metabolism.

Metabolic engineering is a key enabling technology for rewiring cellular metabolism to enhance production of chemicals, biofuels, and materials from renewable resources. However, how to make cells into efficient factories is still challenging due to its robust metabolic networks. To open this door, metabolic engineering has realized great breakthroughs through three waves of technological research and innovations, especially the third wave. To understand the third wave of metabolic engineering better, we discuss its mainstream strategies and examples of its application at five hierarchies, including part, pathway, network, genome, and cell level, and provide insights as to how to rewire cellular metabolism in the context of maximizing product titer, yield, and productivity. Finally, we highlight future perspectives on metabolic engineering for the successful development of cell factories.

Metabolic Engineering

Systematic discovery of pathogen effector functions across human pathogens and pathways.

Pathogens deploy effector proteins to exploit host cell biology, and most effector open reading frames (ORFs) are rapidly evolving and lack functional annotation. We developed the effector ORFeome (eORFeome), a scalable functional genomics platform encompassing 3,835 effector ORFs from diverse viruses, bacteria, and parasites. High-throughput barcoded screens across nuclear factor κB (NF-κB), apoptosis, p53, cGAS-STING, and major histocompatibility complex class I (MHC class I) pathways revealed novel pathway-modulating functions for hundreds of uncharacterized eORFs, unexpected activities of known effectors, and distinct pathway-specific functions encoded by single ORFs. Illustrating the power of this approach, we identified HHV6A U14 as a p53 antagonist, HHV7 U21 as a dual-function STING antagonist and MHC-I antigen display inhibitor, and adenoviral 13.6K/i-leader protein as a de novo-evolved TAP inhibitor that suppresses MHC-I display. These results establish a general framework for systematic effector annotation, uncover new mechanisms of host-pathogen interaction across kingdoms, and highlight pathogen effectors as a versatile toolkit for rewiring and probing human cellular pathways.

Humans

Signaling Pathways Regulating Redox Balance in Cancer Metabolism.

The interplay between rewiring tumor metabolism and oncogenic driver mutations is only beginning to be appreciated. Metabolic deregulation has been described for decades as a bystander effect of genomic aberrations. However, for the biology of malignant cells, metabolic reprogramming is essential to tackle a harsh environment, including nutrient deprivation, reactive oxygen species production, and oxygen withdrawal. Besides the well-investigated glycolytic metabolism, it is emerging that several other metabolic fluxes are relevant for tumorigenesis in supporting redox balance, most notably pentose phosphate pathway, folate, and mitochondrial metabolism. The relationship between metabolic rewiring and mutant genes is still unclear and, therefore, we will discuss how metabolic needs and oncogene mutations influence each other to satisfy cancer cells' demands. Mutations in oncogenes, i.e., PI3K/AKT/mTOR, RAS pathway, and MYC, and tumor suppressors, i.e., p53 and liver kinase B1, result in metabolic flexibility and may influence response to therapy. Since metabolic rewiring is shaped by oncogenic driver mutations, understanding how specific alterations in signaling pathways affect different metabolic fluxes will be instrumental for the development of novel targeted therapies. In the era of personalized medicine, the combination of driver mutations, metabolite levels, and tissue of origins will pave the way to innovative therapeutic interventions.

OXPHOS

Hepatitis C Virus Enhances Lysosome-Associated Membrane Protein 2 A Transcription Through Nuclear Factor Erythroid 2-Related Factor 2 to Support Viral Replication.

Hepatitis C virus (HCV) establishes persistent infection by rewiring host stress-response pathways. Chaperone-mediated autophagy (CMA) contributes to HCV replication, but it remains unclear whether HCV regulates lysosome-associated membrane protein 2 A (LAMP-2A), the rate-limiting receptor for CMA. Here, we examined LAMP-2A regulation in HCV-infected Huh-7.5 cells. HCV infection increased LAMP-2A promoter activity, mRNA, and protein abundance, indicating transcriptional upregulation. Among candidate stress-responsive transcription factors, nuclear factor erythroid 2-related factor 2 (NRF2), hypoxia-inducible factor 1α (HIF-1α), and nuclear factor of activated T cells 1 (NFAT1) were elevated in infected cells. However, promoter mutagenesis identified NRF2 as the principal direct regulator. Mutation of the NRF2-responsive antioxidant response element markedly reduced basal and HCV-induced LAMP-2A promoter activity. Chromatin immunoprecipitation assays revealed NRF2 association with the LAMP-2A promoter, and HCV infection increased nuclear accumulation and Ser40 phosphorylation of NRF2. Functionally, shRNA-mediated knockdown of LAMP-2A reduced intracellular HCV RNA and protein levels. These findings identify an NRF2-LAMP-2A regulatory axis engaged during HCV infection and support a model in which HCV upregulates LAMP-2A to establish a cellular environment favorable for viral replication.

Hepacivirus

Flavonoid biosynthesis mediated by GmF3Hs contributes to drought tolerance in soybean.

Flavonoids are central to abiotic stress responses, yet the specific signaling roles and evolutionary dynamics of flavonoid biosynthetic intermediates in crop drought adaptation remain elusive. Here, we demonstrate that dihydrokaempferol (DHK) and dihydroquercetin (DHQ), specific intermediate products of the soybean flavanone 3-hydroxylases GmF3H1/2, function as potent signaling molecules that mitigate drought stress. Exogenous DHK/DHQ promoted abscisic acid-dependent stomatal closure and enhanced drought tolerance across diverse dicot species, including soybean and tobacco, highlighting a broadly conserved stress-mitigating signaling mechanism. CRISPR/Cas9-generated gmf3hs double mutants exhibited severe drought hypersensitivity due to compromised redox homeostasis and defective stomatal regulation, which could be specifically rescued by DHK/DHQ application. Furthermore, the loss of GmF3H triggered a distinct reproductive trade-off under stress, leading to increased pod initiation but severe filling defects. Multiomics network analysis revealed extensive rewiring of broader stress-responsive pathways and identified upstream transcription factors, among which GmPHL11 directly binds to and activates the GmF3H1 promoter; overexpression of GmPHL11 promoted DHK accumulation and enhanced drought stress tolerance in soybean hairy roots. Finally, population genomic analyses demonstrated that the GmF3H1H1 haplotype, which confers superior enzymatic activity and robust root growth under drought stress, might have undergone positive selection during soybean domestication. Collectively, our findings redefine the role of GmF3H-derived specific intermediates as potent signaling molecules, providing comprehensive mechanistic and evolutionary insights into flavonoid-mediated drought resilience, developmental trade-offs, and molecular breeding in crops.

Drought Resistance

Habitat-Adapted Fungal Symbionts Promote Salt Stress Tolerance Through Distinct Root Mechanisms and Shared Shoot Regulatory Networks in Arabidopsis thaliana.

Salinity is a major constraint to crop productivity. Beneficial plant-fungus interactions represent a promising strategy to enhance stress resilience. Here, we investigated fungal endophytes isolated from the roots of Oryza sativa cultivated in saline-prone marshlands of the Guadalquivir River, Spain. From a collection of 38 isolates, five salt-tolerant strains exhibiting plant growth-promoting activity were identified, including a previously uncharacterized Reticulascus sp. strain S5. Co-cultivation assays with the non-native host plant Arabidopsis thaliana demonstrated that S5 increased the root and shoot biomass under salt stress. To elucidate the underlying molecular mechanisms, a comprehensive RNA-Seq analysis of the roots and shoots under control and saline conditions was performed. Fungal colonization induced pronounced transcriptomic changes, particularly in the shoots, including rewiring of the auxin- and abscisic acid-related pathways and the induction of genes associated with cell wall remodeling. Concurrently, defense-related processes, including glucosinolate biosynthesis and ethylene signaling, were broadly repressed, suggesting attenuated stress perception in colonized plants. In the roots, S5 inoculation suppressed the expression of genes involved in root hair development and cell wall organization, indicating a fungus-driven reconfiguration of root development. Moreover, comparative analysis with Fusarium sp. K-23, a fungus that has previously been demonstrated to promote plant growth under salinity stress, revealed distinct root-associated mechanisms but convergence on a shared regulatory module in shoots involving ABA-responsive transcription factors and osmotic stress regulators. Collectively, our findings demonstrate that Reticulascus sp. S5 enhances plant salt stress tolerance through the coordinated transcriptional reprogramming of growth, hormone signaling, and stress responses, highlighting a possible potential of habitat-adapted endophytes for sustainable crop improvement.

Arabidopsis

The TRIM-cancer paradox: BCG as a programmable vaccine platform and a mechanistic probe for rational immunotherapy design.

BCG, a first-generation live vaccine, is being reconsidered as an immunological platform. Interest in its heterologous protection intensified during the pandemic. However, large-scale clinical trials revealed inconsistencies in the efficacy of native BCG. This review argues that BCG's main value lies in its potential as a modifiable vector platform and in its ability to reveal tractable molecular pathways for therapeutic design. This review summarizes the molecular basis of BCG-induced trained immunity (TRIM), focusing on PRR-driven signaling, metabolic rewiring, and epigenetic remodeling in innate immune cells and hematopoietic progenitors. It also maps their convergence with pathways that sustain pro-tumorigenic inflammation. The original conceptual paradigm of the "TRIM-Cancer Paradox" is presented. This paradigm posits that the same innate immune circuits that mediate protective heterologous responses can drive tumor-promoting inflammation and immune escape under conditions of chronic dysregulation. Recombinant BCG (rBCG) is further analyzed as a strategy to rationally amplify or redirect these circuits, the current clinical landscape of BCG-based interventions across various diseases and oncological malignancies is highlighted, and specific molecular nodes that could be exploited to increase the precision, efficacy, and safety of rBCG-based therapies are identified. Overall, this review proposes BCG a programmable immunological platform and to use the TRIM-Cancer Paradox as a novel design principle for next-generation rBCG platforms that transcend traditional vaccinology and cancer immunotherapy applications.

Humans

MicroRNAs and predicted targets in the switch from monolayered to spheroids of cholangiocarcinoma cells.

BACKGROUND: Extrahepatic cholangiocarcinoma (eCCA) is characterized by marked molecular heterogeneity and limited therapeutic options. MicroRNAs (miRNAs) are key post-transcriptional regulators of cancer-related pathways, but their contribution to tumor adaptation in physiologically relevant models remains poorly understood. Three-dimensional (3D) tumor spheroids better mimic in vivo conditions than conventional two-dimensional (2D) cultures. METHODS: We compared miRNA expression profiles in two eCCA cell lines (Sk-ChA-1 and Mz-ChA-1) grown as monolayers (2D) or multicellular tumor spheroids (3D). MiRNA profiling was performed using NanoString technology. Predicted targets were analyzed by over-representation analysis, and selected miRNAs and genes were validated by RT-qPCR and ELISA-based assays. RESULTS: 3D growth induced extensive miRNA remodeling, with distinct (54 deregulated in Sk-ChA-1 and 29 in Mz-ChA-1 cells) and partially overlapping signatures (miR-1283, miR-577, and miR-2113). Among the shared miRNAs, predicted targets included DUSP10 and RBFOX1, while in spheroids, cell-specific multiple miRNAs converged on shared targets (TNRC6B, SMARCAD1, ATG14, HMGA2, and CLOCK) displaying inverse expression patterns. The transcriptional program impacted MAPK signaling, enhanced EMT, and activated stress-adaptive networks but attenuated proliferation in 3D Sk-ChA-1 cells, while Mz-ChA-1 cells retained a more epithelial and proliferative profile. In this context, we point out the involvement of miR-19b-3p using anti-miR transfection experiments. CONCLUSION: Our findings reveal a miRNA-driven regulatory landscape associated with 3D growth in eCCA, linking tumor architecture to signaling rewiring and cellular plasticity, and highlight potentially druggable candidate targets and pathways to investigate as candidates using inhibitors or gene therapy-based interventions.

Humans

Inactivation of the SLC25A1 gene during embryogenesis induces a unique senescence program controlled by p53.

Germline inactivating mutations of the SLC25A1 gene contribute to various human disorders, including Velocardiofacial (VCFS), DiGeorge (DGS) syndromes and combined D/L-2-hydroxyglutaric aciduria (D/L-2HGA), a severe systemic disease characterized by the accumulation of 2-hydroxyglutaric acid (2HG). The mechanisms by which SLC25A1 loss leads to these syndromes remain largely unclear. Here, we describe a mouse model of SLC25A1 deficiency that mimics human VCFS/DGS and D/L-2HGA. Surprisingly, inactivation of both Slc25a1 alleles results in alterations in the development of multiple organs, and in a severe proliferation defect by activating two senescence programs, oncogene-induced senescence (OIS) and mitochondrial dysfunction-induced senescence (MiDAS), which converge upon the induction of the p53 tumor suppressor. Mechanistically, cells and tissues with dysfunctional SLC25A1 protein undergo metabolic and transcriptional rewiring leading to the accumulation of 2HG via a non-canonical pathway and to the depletion of nicotinamide adenine dinucleotide, NAD+, which trigger senescence. Replenishing the pool of NAD+ or promoting the clearance of 2HG rescues the proliferation defect of cells with dysfunctional SLC25A1 in a cooperative fashion. Further, removal of p53 activity via RNA interference restores proliferation, indicating that p53 acts as a critical barrier to the expansion of cells lacking functional SLC25A1. These findings reveal unexpected pathogenic roles of senescence and of p53 in D/L-2HGA and identify potential therapeutic strategies to correct salient molecular alterations driving this disease.

Animals

Synergistic targeting of cancer cells through simultaneous inhibition of key metabolic enzymes.

As cancer cell specific rewiring of metabolic networks creates potential therapeutic opportunities, we conducted a synthetic lethal screen utilizing inhibitors of metabolic pathways. Simultaneous administration of (R)-GNE-140 and BMS-986205 (Linrodostat) preferentially halted proliferation of ovarian cancer cells, but not of their non-oncogenically transformed progenitor cells. While (R)-GNE-140 inhibits lactate dehydrogenase (LDH)A/B and thus effective glycolysis, BMS-986205, in addition to its known inhibitory activity on Indoleamine 2,3-dioxygenase (IDO1), also restricts oxidative phosphorylation (OXPHOS), as revealed here. BMS-986205, which is being tested in multiple Phase III clinical trials, inhibits the ubiquinone reduction site of respiratory complex I and thus compromises mitochondrial ATP production. The energetic catastrophe caused by simultaneous interference with glycolysis and OXPHOS resulted in either cell death or the induction of senescence in tumor cells, with the latter being eliminated by senolytics. The frequent synergy observed with combined inhibitor treatment was comprehensively confirmed through testing on tumor cell lines from the DepMap panel and on human colorectal cancer organoids. These experiments revealed highly synergistic activity of the compounds in a third of the tested tumor cell lines, correlating with alterations in genes with known roles in metabolic regulation and demonstrating the therapeutic potential of metabolic intervention.

Humans

Metabolic Engineering of Probiotic Saccharomyces boulardii Enables Intestinal 3-Hydroxybutyrate Delivery and Alters Short-Chain Fatty Acid Profiles in Mice.

3-Hydroxybutyric acid (3-HB) is a bioactive ketone body involved in the regulation of intestinal inflammation and metabolic homeostasis. Although engineered bacterial probiotics have been developed for localized 3-HB delivery, their susceptibility to antibacterial antibiotics may limit their use during concurrent antibiotic treatment. The probiotic yeast Saccharomyces boulardii offers an alternative host for intestinal 3-HB delivery because of its compatibility with antibacterial antibiotics and the availability of well-established genetic engineering tools. Here, we engineered S. boulardii for 3-HB production using Cas9-mediated genome editing. A heterologous 3-HB biosynthetic pathway was introduced into S. boulardii MYA-797, and endogenous acetyl-CoA and ethanol metabolism was subsequently rewired by overexpressing ACS1, deleting ADH1, and overexpressing ADH7. The optimized strain, SbDY02, produced 1.7 g/L 3-HB under microaerobic conditions. Oral administration of SbDY02 to C57BL/6J mice increased fecal 3-HB and short-chain fatty acid (SCFA) concentrations by 1.89-fold and 1.68-fold, respectively, compared with mice receiving the parental strain. Repeated administration also increased fecal acetate and circulating total SCFAs, butyrate, and propionate. In human colonic epithelial cells, purified 3-HB attenuated lipopolysaccharide-induced p38 MAPK phosphorylation, supporting its direct activity toward inflammation-associated epithelial signaling. To our knowledge, this study provides the first demonstration of a 3-HB-producing probiotic yeast and links central metabolic engineering of S. boulardii with increased 3-HB availability, altered SCFA profiles, and a host-relevant epithelial response.

3-hydroxybutyrate

Rewiring Carbon Metabolism in Bacillus methanolicus via Heterologous Phosphoketolase Expression Enhances Biomass Yield From Methanol and Reduces CO2 Loss.

Methylotrophic microbes are attractive alternatives to traditional heterotrophic production platforms, yet their efficiency is constrained by carbon loss through pyruvate decarboxylation and the oxidative branch of the RuMP cycle. The phosphoketolase (PKT) pathway provides a carbon-conserving alternative by cleaving fructose-6-phosphate and/or xylulose-5-phosphate into acetyl-phosphate, which can subsequently be converted to acetyl-coA without pyruvate decarboxylation. The remaining carbon intermediates are recycled through central metabolism to regenerate RuMP cycle intermediates without direct CO2 release. Here, we engineered this strategy in Bacillus methanolicus, a thermophilic methylotroph with strong industrial potential. We first established a versatile expression toolkit comprising inducible and constitutive promoters, benchmarked using an sfGFP reporter. Leveraging this system, we heterologously expressed the phosphoketolase B (pktB) gene from Methylotuvimicrobium buryatense 5GB1C which increased methanol-to-biomass yields by 18%-24% relative to controls and reduced biogenic CO2 production by 9%-12%. Chromosomal integration of pktB preserved these gains, demonstrating stability without reliance on plasmid-based expression. Together, these results show that PKT-driven metabolic rewiring enhances substrate yields in B. methanolicus and provides a scalable strategy to improve methylotrophic bioprocesses. This work expands the metabolic engineering toolbox for methylotrophs and highlights carbon-conserving pathway design as a key lever for advancing single carbon (C1) biomanufacturing.

Bacillus

Epigenetic and metabolic reprogramming of innate immune cells establishes immunological memory in the Schistosomiasis vector snail Biomphalaria glabrata.

Innate immune memory enables non-vertebrates to mount faster and more effective immune responses upon re-exposure to a previously encountered pathogen, yet its cellular and molecular bases remain poorly understood. The freshwater snail Biomphalaria glabrata, intermediate host of the human parasite Schistosoma mansoni, provides a powerful model to investigate this phenomenon. Here, we show that innate immune memory in B. glabrata is carried by hemocytes and relies on profound metabolic and epigenetic reprogramming initiated during primary infection. Using an integrative multi-omics approach combining transcriptomics, chromatin accessibility profiling, whole-genome bisulfite sequencing and targeted metabolomics, we reveal that the first parasite encounter induces a stable rewiring of hemocyte metabolism and chromatin landscape. This reprogramming primes hemocytes for a massive and rapid transcriptional response upon secondary challenge, characterized by an immune shift toward highly specific humoral effector pathways. Metabolic analyses demonstrate an early switch toward aerobic glycolysis, altered tricarboxylic acid cycle activity and amino acid metabolism, consistent with a Warburg-like metabolic state previously described in vertebrate trained immunity. Notably, metabolic and epigenetic remodeling occurs primarily during the primary infection and remains stable upon secondary exposure, suggesting that immune memory is encoded prior to pathogen re-encounter. Together, our results identify conserved metabolic and epigenetic mechanisms underlying innate immune memory in a non-vertebrate host and provide direct evidence that hemocyte-mediated innate immune memory in B. glabrata shares core features with trained immunity described in vertebrates.

Animals