Supply Pathways Research Articles

Inhibition of selenium supply function of selenoprotein p through adduct formation by sulforaphane

Selenium is a potent nucleophile essential for selenoenzymes, such as glutathione peroxidase (also known as GSH-Px; GPX; GPx) and selenoprotein P (also known as SelP; SEPP1; SELENOP; SeP). SeP is predominantly secreted from the liver and functions as a selenium carrier in plasma. We previously found that sulforaphane (SFN), an electrophilic phytochemical, reduces SeP production in cultured hepatocytes and mouse liver, however, the effect of electrophilic modification of SeP by SFN on selenium transport and metabolism remains unclear. In the present study, we demonstrate that sulforaphane covalently modifies selenocysteine/cysteine residues of SeP using an acidic biotin PAEC5 maleimide labeling assay, which allows for focused-labeling of selenocysteine residues. Although the SFN-SeP adduct can be taken up by HepG2 cells and degraded by the lysosome, it was less effective in inducing GPx expression. Our findings indicate that SFN disrupts the selenium supply pathway through the formation of the SeP-SFN adduct.

Static and Dynamic Regulation of Precursor Supply Pathways to Enhance Raspberry Ketone Synthesis from Glucose in Escherichia coli.

Raspberry ketone (RK), a natural product derived from raspberry fruit, is commonly utilized as a flavoring agent in foods and as an active component for weight loss. Metabolic engineering has enabled microorganisms to produce RK more efficiently and cost-effectively. However, the biosynthesis of RK is hindered by an unbalanced synthetic pathway and a deficiency of precursors, including tyrosine and malonyl-CoA. In this study, we constructed and optimized the RK synthetic pathway in Escherichia coli using a static metabolic engineering strategy to enhance the biosynthesis of tyrosine from glucose, thereby achieving the de novo production of RK. Additionally, the synthetic and consumption pathways of malonyl-CoA were dynamically regulated by p-coumaric acid-responsive biosensor to balance the metabolic flux distribution between cell growth and RK biosynthesis. Following pathway optimization, the medium components and fermentation conditions were further refined, resulting in a significant increase in the RK titer to 415.56 mg/L. The optimized strain demonstrated a 32.4-fold increase in the RK titer while maintaining a comparable final OD600 to the initial strain. Overall, the implemented static and dynamic regulatory strategies provide a novel approach for the efficient production of RK, taking into account cell viability and growth.

Neutrophils with low production of reactive oxygen species are activated during immune priming and promote development of arthritis

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease mediated by immune cell dysfunction for which there is no universally effective prevention and treatment strategy. As primary effector cells, neutrophils are important in the inflammatory joint attack during the development of RA. Here, we used single-cell sequencing technology to thoroughly analyze the phenotypic characteristics of bone marrow-derived neutrophils in type II collagen (COL2)-induced arthritis (CIA) models, including mice primed and boosted with COL2. We identified a subpopulation of neutrophils with high expression of neutrophil cytoplasmic factor 1 (NCF1) in primed mice, accompanied by a characteristic reactive oxygen species (ROS) response, and a decrease in Ncf1 expression in boosted mice with the onset of arthritis. Furthermore, we found that after ROS reduction, arthritis occurred in primed mice but was attenuated in boosted mice. This bidirectional effect of ROS suggested a protective role of ROS during immune priming. Mechanistically, we combined functional assays and metabolomics identifying Ncf1-deficient neutrophils with enhanced migration, chemotactic receptor CXCR2 expression, inflammatory cytokine secretion, and Th1/Th17 differentiation. This alteration was mainly due to the metabolic reprogramming of Ncf1-deficient neutrophils from an energy supply pathway dominated by gluconeogenesis to an inflammatory immune pathway associated with the metabolism of histidine, glycine, serine, and threonine signaling, which in turn induced arthritis. In conclusion, we have systematically identified the functional and inflammatory phenotypic characteristics of neutrophils under ROS regulation, which provides a theoretical basis for understanding the pathogenesis of RA, to further improve prevention strategies and identify novel therapeutic targets.

Autotrophic Sulfur-Driven Partial Denitrification as a Sustainable Nitrite Supply Pathway for Anammox: Insights on Enhanced Nitrogen Removal and Microbial Synergies

Autotrophic Sulfur-Driven Partial Denitrification as a Sustainable Nitrite Supply Pathway for Anammox: Insights on Enhanced Nitrogen Removal and Microbial Synergies

Engineering yeast for high-level production of β-farnesene from sole methanol

Methanol, a rich one-carbon feedstock, can be massively produced from CO2 by the liquid sunshine route, which is helpful to realize carbon neutrality. β-Farnesene is widely used in the production of polymers, surfactants, lubricants, and also serves as a suitable substitute for jet fuel. Constructing an efficient cell factory is a feasible approach for β-farnesene production through methanol biotransformation. Here, we extensively engineered the methylotrophic yeast Ogataea polymorpha for the efficient bio-production of β-farnesene using methanol as the sole carbon source. Our study demonstrated that sufficient supply of precursor acetyl-CoA and cofactor NADPH in an excellent yeast chassis had a 1.3-fold higher β-farnesene production than that of wild-type background strain. Further optimization of the mevalonate pathway and enhancement of acetyl-CoA supply led to a 7-fold increase in β-farnesene accumulation, achieving the highest reported sesquiterpenoids production (14.7 g/L with a yield of 46 mg/g methanol) from one-carbon feedstock under fed-batch fermentation in bioreactor. This study demonstrates the great potential of engineering O. polymorpha for high-level terpenoid production from methanol.

Spatial and temporal evolution of cost-competitive offshore hydrogen in China: A techno-economic analysis

China's ascendancy as the premier offshore wind power developer and principal hydrogen consumer underscores the expanding demand for green hydrogen, which is vital to its decarbonization trajectory. Offshore wind power is recognized as a crucial pathway for the future supply of green hydrogen, and further exploration of its development potential and economic viability can provide important insights for optimizing resource allocation, reducing greenhouse gas emissions, and ensuring energy security. This study analyzed the potential and regional economic differences in offshore wind energy for hydrogen production in China's coastal regions by considering the temporal evolution of techno-economic parameters and the spatial and temporal characteristics of geospatial resources. The findings suggest a potential hydrogen production capacity of 434–493 Mt/year in Chinese waters, with the average levelized cost of hydrogen projected to decline from 7.13 $/kgH2 in 2025 to 3.77 $/kgH2 by 2050, which is attributed to advancements in wind turbine technology and cost reductions in components. By 2030, hydrogen production of 40 Mt/year is expected to be cost-competitive, especially in Liaoning and Hebei, with projections indicating an increase to 435 Mt/year by 2050. Notably, floating wind power, contributing to 54 % of China's total offshore hydrogen capacity, holds significant promise for provinces such as Guangdong, Hainan, and Zhejiang. The study conclude that China's offshore hydrogen production has significant potential, with cost-competitive production achievable by 2030 and broad economic viability anticipated by 2050.

Engineering Streptomyces albus B4 for Enhanced Production of (R)-Mellein: A High-Titer Heterologous Biosynthesis Approach.

The natural compound (R)-(-)-mellein exhibits antiseptic and fungicidal activities. We investigated its biosynthesis using the polyketide synthase encoded by SACE_5532 (pks8) from Saccharopolyspora erythraea heterologously expressed in Streptomyces albus B4, a chassis chosen for its fast growth, genetic manipulability, and ample large short-chain acyl-CoA precursor supply. High-level heterologous (R)-(-)-mellein yield was achieved by pks8 overexpression and duplication. The precursor supply pathways were strengthened by overexpression of SACE_0028 (encoding acetyl-CoA carboxylase) and four genes involved in β-oxidation (fadD, fadE, fadB, and fadA). Cell growth inhibition by (R)-(-)-mellein production at high concentration was relieved by in situ adsorption using Amberlite XAD16 resin. The final strain, B4mel12, produced (R)-(-)-mellein at 6395.2 mg/L in shake-flask fermentation. Overall, this is the first report of heterologous (R)-(-)-mellein synthesis in microorganism with a high titer. (R)-(-)-mellein prototype in this study opens a possibility for the overproduction of valuable melleins in S. albus B4.

Transport Pathways for Iron Supply to the Australian Antarctic Ridge Phytoplankton Bloom

AbstractBiological productivity in the Southern Ocean is modulated by iron availability. Every summer, a large phytoplankton bloom forms northwest of the Ross Sea, above the Antarctic Australian Ridge (AAR), due to a plume of iron‐rich waters. Here, we investigate the origin and trajectories of these iron‐rich waters by analyzing water mass observations and Lagrangian experiments. Output from the Southern Ocean State Estimate (SOSE) and in situ measurements reveal that iron‐rich AAR bloom waters share properties with Modified Circumpolar Deep Water (MCDW), which forms on the Antarctic shelf‐slope. The Lagrangian experiments are conducted using SOSE velocities. Bloom waters tracked with virtual Lagrangian particles highlight an along isopycnal pathway of MCDW from Antarctica's shelf‐slope to the AAR bloom site, illustrating advection of these waters by the Balleny Gyre. These results are supported by temperature‐salinity analyses, which show a correlation between waters advected northwards; MCDW properties; and high iron concentrations.

Micro-nano H2 bubbles enhanced hydrodehalogenation of 3-chloro-4-fluoroaniline: Mass transfer and action mechanism

3-chloro-4-fluoraniline (FCA) is an important intermediate for the synthesis of antibiotics, herbicides and insecticides, and has significant environmental health hazards. Catalytic hydrogenation technology is widely used in pretreatment of halogenated organics due to its simple process and excellent performance. However, compared with the research of high activity hydrogenation catalyst, the research of efficient utilization of hydrogen source under mild conditions is not sufficient. In this work, micro-nano H2 bubbles are produced in situ by electrolytic water and active metal replacement, and their apparent properties are studied. The result show that the H2 bubbles have a size distribution in the range of 150–900 nm, which can rapidly reduce the REDOX potential of the water and maintain it in a hydrogen-rich state for a long time. Under the action of Pd/C catalyst, atomic hydrogen (H•) produced by dissociative adsorption can sequentially hydrogenate FCA to aniline. The H• utilization ratios of the above two hydrogen supply pathways reach 6.20% and 4.94% respectively, and H2 consumption is reduced by tens of times (≥50 → ≈1.0 mL/min). The research provides technical support for the efficient removal of halogenated refractory pollutants in water and the development of hydrogen economy.

P2M systems based on proton-conducting solid oxide cells: Future prospects and costs of renewable methanol production

As consequence of the transition towards sustainable energy sources, the future production of liquid energy carriers (e.g. methanol) via H2 supply pathways utilizing water electrolyzers (power-to-liquid) will most likely be based on fluctuating grid electricity or islanded renewable inputs. As a result, these production processes are subject to fluctuating operating conditions and varying production capacities, ultimately leading to uncertainties with respect to their process economics and profitability. Therefore, the impact of different electricity supply-side scenarios (static grid and intermittent grid or renewable supply) on the production economics of power-to-liquid processes needs to be assessed thoroughly for the upcoming decades. Methanol is considered as an essential base chemical which is widely known for its versatility and broad potential use contexts in future chemical industries and energy storage applications. Methanol production pathways powered by renewable electricity sources, also known as power-to-methanol processes, are characterized by low specific life-cycle emissions and are therefore of paramount interest. One possible renewable process chain features proton-conducting high temperature electrolyzers combined with a direct hydrogenation of CO2. In this paper, a techno-economic forecast study of this process chain is presented and specific production costs of renewable methanol under different electricity supply scenarios are determined and discussed for the years 2030 and 2050. The studies showed that flexible grid-supported scenarios through direct spot-market participation and renewable scenarios based on wind onshore production enable the largest production cost reduction potential in the upcoming decades. Minimum production costs of 740 € t−1MeOH (2030) and 415 € t−1MeOH (2050) are determined for a flexible operation of the system with spot-market participation, benefitting from times of low or even negative electricity prices. Among the renewable production scenarios, islanded power-to-methanol systems coupled to wind onshore plants were identified as the most beneficial configuration with ascertained production costs as low as 820 € t−1MeOH and 353 € t−1MeOH by 2030 and 2050, respectively.

Research progress on the relationship between Nesfatin-1 and glucose metabolism.

Nesfatin-1 is a neuropeptide hormone known for its biological functions, including inhibiting food intake, regulating glucose and lipid metabolism, promoting apoptosis, and providing anti-inflammatory and anti-tumor effects. Glucose metabolism is a crucial pathway for the body's energy supply. Current research has demonstrated that Nesfatin-1 can affect glucose metabolism through various mechanisms, such as inhibiting food intake, regulating enzyme activity, and improving insulin resistance, though the findings are not entirely consistent. Investigating the relationship between Nesfatin-1 and glucose metabolism may offer new insights into the diagnosis and treatment of diseases related to glucose metabolism disorders.

Robust superhydrophobic Poly(vinylidene fluoride) membranes with spherulitic surface morphology against wetting and scaling in membrane distillation

Membrane distillation (MD) offers a theoretically complete interception of salts, presenting a promising desalination pathway for freshwater supply. However, conventional hydrophobic membranes fail to desalinate water containing surfactants or supersaturated gypsum over prolonged periods. To address wetting and scaling challenges, we developed a superhydrophobization methodology for poly (vinylidene fluoride) membranes by in situ controlling spherulitic surface morphology through thermally induced phase separation. The major advantages of this one-step strategy lie in its fluorination-free, template-free, and nanoparticle-free. The as-prepared membranes exhibit a rough morphology and superhydrophobic characters with high air-trapping pockets. They demonstrate stable vapor fluxes and high salt rejections (>99 %) when used in desalination processes for saline water containing 0.6 mM sodium dodecyl sulfate, 0.03 mM cetyltrimethylammonium bromide, or gypsum solution with a saturation index of 1.1. Also, the outstanding anti-wetting and anti-scaling properties were demonstrated using synthetic shale gas wastewater. The formation of an air layer on the integrated spherulitic surface highlights the local kinetic barrier and slippery surface, effectively preventing the attachment of amphiphilic surfactants and mineral ions. Importantly, due to the membrane's structural integrity, the spherulitic surface displays high robustness and minimal impact from abrasion cycles and ultrasonication. This work exemplifies a facile strategy to engineer micro-/nano-spherulitic surface morphology for robust superhydrophobic membranes used in MD desalination.

Zinc-Based ROS Amplifiers Trigger Cancer Chemodynamic/Ion Interference Therapy Through Self-Cascade Catalysis.

Nanozyme-mediated chemodynamic therapy has emerged as a promising strategy due to its tumor specificity and controlled catalytic activity. However, the poor efficacy caused by low hydrogen peroxide (H2O2) levels in the tumor microenvironment (TME) poses challenges. Herein, an H2O2 self-supplying nanozyme is constructed through loading peroxide-like active platinum nanoparticles (Pt NPs) on zinc peroxide (ZnO2) (denoted as ZnO2@Pt). ZnO2 releases H2O2 in response to the acidic TME. Pt NPs catalyze the hydroxyl radical generation from H2O2 while reducing the mitigation of oxidative stress by glutathione, serving as a reactive oxygen (ROS) amplifier through self-cascade catalysis. In addition, Zn2+ released from ZnO2 interferes with tumor cell energy supply and metabolism, enabling ion interference therapy to synergize with chemodynamic therapy. In vitro studies demonstrate that ZnO2@Pt induces cellular oxidative stress injury through enhanced ROS generation and Zn2+ release, downregulating ATP and NAD+ levels. In vivo assessment of anticancer effects showed that ZnO2@Pt could generate ROS at tumor sites to induce apoptosis and downregulate energy supply pathways associated with glycolysis, resulting in an 89.7% reduction in tumor cell growth. This study presents a TME-responsive nanozyme capable of H2O2 self-supply and ion interference therapy, providing a paradigm for tumor-specific nanozyme design.

Decomposition of physical processes controlling EASM precipitation changes during the mid-Piacenzian: new insights into data–model integration

The mid-Piacenzian warm period (MPWP, ~3.264–3.025 Ma) has gained widespread interest due to its partial analogy with future climate. However, quantitative data–model comparison of East Asian Summer Monsoon (EASM) precipitation during the MPWP is relatively rare, especially due to problems in decoding the imprint of physical processes to climate signals in the records. In this study, pollen-based precipitation records are reconstructed and compared to the multi-model ensemble mean of the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). We find spatially consistent precipitation increase in most simulations but a spatially divergent change in MPWP records. We reconcile proxy data and simulation by decomposing physical processes that control precipitation. Our results 1) reveal thermodynamic control of an overall enhancement of EASM precipitation and 2) highlight a distinct control of thermodynamic and dynamical processes on increases of tropical and subtropical EASM precipitation, reflecting the two pathways of water vapor supply that enhance EASM precipitation, respectively.

Nutrient and organic substances emissions from diffuse sources to the rivers of Ukrainian Carpathians

Formulation of the problem. The transition from territorial-administrative to basin-based water resources management in Ukraine requires an assessment of the load of water bodies with pollutants from diffuse and point sources. Among the various components of the chemical composition of water entering water bodies, organic matter and nutrients are the most important. The Danube is the second largest river in Europe, with a basin covering the territories of 19 countries and is an important transportation waterway. Within Ukraine, the Danube is divided into the Lower Danube sub-catchment and the Tisza, Prut, and Siret River basins within the Carpathian region. The scientific results presented in this paper were obtained during research within the framework of state budgetary research works of the UHMI, the implementation of which will contribute to the further development of knowledge in the field of hydrometeorology. The results presented in the publication are important for supplementing information when writing the Danube River Basin Management Plan, which is being developed in accordance with Ukraine's obligations under the Association Agreement with the European Union. Aim of the study. To calculate the supply of nutrients and organic matter from diffuse sources to the rivers of the Danube basin within the Ukrainian Carpathians. Methods. Monitoring data of organic substances and nutrients provided by the Danube Hydrometeorological Observatory (the state surface water monitoring network of the State Emergency Service of Ukraine) for 2018 were used for calculations. To assess the load of water bodies by diffuse sources, a conceptual scheme was developed that allowed to take into account the main pathways of substances supply, i.e precipitation; water runoff from arable land, forests, meadows and pastures, built-up areas, rock outcrops, as well as from the population of rural regions without sewage systems. Scientific novelty. For the first time: the load of nutrients and organic matter in the Danube rivers within the Ukrainian Carpathians by the sources of their income was evaluated; it was found that agricultural land is the main source of emissions of inorganic nitrogen and phosphorus compounds. Practical value. The analysis of the diffuse load by nutrients and organic matter in the Danube rivers can be used as an important part of the River Basin Management Plan. The results of the calculations can also be used to develop measures to achieve certain environmental objectives. Results. The main source of organic matter in the water of rivers of the Carpathian region ere agricultural enterprises locating within rural settlements that are not equipped with sewage systems. Surface water of Prut and Tisza River basins is the most polluted by organic matter. By source, the nutrient emissions are distributed as follows. For the Tisza and Prut rivers, more than 50% of the total nitrogen compounds emissions come from agricultural land, while for the Siret River the source of nitrogen compounds are forests (46% of the total nitrogen emissions). Accordingly, the total phosphorus runoff for the Tisza and Prut rivers was distributed as follows: the dominant share (up to 45%) comes from agricultural land, the load caused by population not connected to the sewerage systems is 36%. For the Siret River, agricultural land and forested areas are of equal shares (33%) among the sources of phosphorus compounds.

Large Flux Supply of NAD(H) under Aerobic Conditions by Candida glycerinogenes.

NAD is a redox coenzyme and is the center of energy metabolism. In metabolic engineering modifications, an insufficient NAD(H) supply often limits the accumulation of target products. In this study, Candida glycerinogenes was found to be able to supply NAD(H) in large fluxes, up to 7.6 times more than Saccharomyces cerevisiae in aerobic fermentation. Aerobic fermentation in a medium without amino nitrogen sources demonstrated that C. glycerinogenes NAD synthesis was not dependent on NAD precursors in the medium. Inhibition by antisense RNA and the detection of transcript levels indicated that the main NAD supply pathway is the de novo biosynthesis pathway. It was further demonstrated that NAD(H) supply was unaffected by changes in metabolic flow through C. glycerinogenes ΔGPD aerobic fermentation (80 g/L ethanol). In conclusion, the ability of C. glycerinogenes to supply NAD(H) in large fluxes provides a new approach to solving the NAD(H) supply problem in synthetic biology.

Comparison of different hydrogen-ammonia energy conversion pathways for renewable energy supply

Hydrogen and ammonia are considered promising energy carriers for renewable energy due to their environmental friendliness and medium- and long-term storage cost advantages. However, a single hydrogen or ammonia energy strategy generally cannot meet the demand, limiting widespread application. Here we consider the whole process of renewable energy generation-transmission-storage-consumption, and propose a hydrogen-ammonia combined operation strategy. Assuming a rated power of 40 MW for generation and 10 MW for demand, we compare five energy conversion pathways: hydrogen or ammonia pipeline transmission, high-voltage alternating current (HVAC) transmission with hydrogen or ammonia storage, and HVAC transmission with hydrogen-ammonia hybrid energy storage. Results indicate that for a transmission distance of 100 km, the most economical pathway is HVAC transmission with hydrogen-ammonia hybrid energy storage, with a net present value (NPV) of 39.31 M$ and a levelized cost of electricity (LCOE) of 0.081 $/kWh. Sensitivity analyses reveal that a 0.01 $/kWh increase in electricity price leads to NPV growths of 11.75–16.02 M$. This pathway achieves zero carbon footprint and saves 4.7 M$ annually in carbon taxes. Compared to traditional production methods, this pathway is equivalent to reducing emissions by 94,189 tons.

Ventilation of the Arabian Sea Oxygen Minimum Zone by Persian Gulf Water

AbstractDense overflows from marginal seas are critical pathways of oxygen supply to the Arabian Sea oxygen minimum zone (OMZ), yet these remain inadequately understood. Climate models struggle to accurately reproduce the observed extent and intensity of the Arabian Sea OMZ due to their limited ability to capture processes smaller than their grid scale, such as dense overflows. Multi‐month repeated sections by underwater gliders off the coast of Oman resolve the contribution of dense Persian Gulf Water (PGW) outflow to oxygen supply within the Arabian Sea OMZ. We characterize PGW properties, seasonality, transport and mixing mechanisms to explain local processes influencing water mass transformation and oxygen fluxes into the OMZ. Atmospheric forcing at the source region and eddy mesoscale activity in the Gulf of Oman control spatiotemporal variability of PGW as it flows along‐shelf off the northern Omani coast. Subseasonally, it is modulated by stirring and shear‐driven mixing driven by eddy‐topography interactions. The oxygen transport from PGW to the OMZ is estimated to be 1.3 Tmol yr−1 over the observational period, with dramatic inter‐ and intra‐annual variability (±1.6 Tmol yr−1). We show that this oxygen is supplied to the interior of the OMZ through the combined action of double‐diffusive and shear‐driven mixing. Intermittent shear‐driven mixing enhances double‐diffusive processes, with mechanical shear conditions (Ri < 0.25) prevailing 14% of the time at the oxycline. These findings enhance our understanding of fine‐scale processes influencing oxygen dynamics within the OMZ that can provide insights for improved modeling and prediction efforts.

Comparative transcriptomic analysis delineates adaptation strategies of Rana kukunoris toward cold stress on the Qinghai-Tibet Plateau

BackgroundCold hardiness is fundamental for amphibians to survive during the extremely cold winter on the Qinghai-Tibet plateau. Exploring the gene regulation mechanism of freezing-tolerant Rana kukunoris could help us to understand how the frogs survive in winter.ResultsTranscriptome of liver and muscle of R. kukunoris collected in hibernation and spring were assisted by single molecule real-time (SMRT) sequencing technology. A total of 10,062 unigenes of R. kukunoris were obtained, and 9,924 coding sequences (CDS) were successfully annotated. Our examination of the mRNA response to whole body freezing and recover in the frogs revealed key genes concerning underlying antifreeze proteins and cryoprotectants (glucose and urea). Functional pathway analyses revealed differential regulated pathways of ribosome, energy supply, and protein metabolism which displayed a freeze-induced response and damage recover. Genes related to energy supply in the muscle of winter frogs were up-regulated compared with the muscle of spring frogs. The liver of hibernating frogs maintained modest levels of protein synthesis in the winter. In contrast, the liver underwent intensive high levels of protein synthesis and lipid catabolism to produce substantial quantity of fresh proteins and energy in spring. Differences between hibernation and spring were smaller than that between tissues, yet the physiological traits of hibernation were nevertheless passed down to active state in spring.ConclusionsBased on our comparative transcriptomic analyses, we revealed the likely adaptive mechanisms of R. kukunoris. Ultimately, our study expands genetic resources for the freezing-tolerant frogs.

Abstract 3155: Metabolic stress induces an intrinsic inflammatory CAF phenotype that regulates stromal architecture in pancreatic cancer

Abstract Macropinocytosis is a critical amino acid supply pathway that fuels the metabolism of tumor cells and cancer-associated fibroblasts (CAFs) in pancreatic ductal adenocarcinoma (PDAC). PDAC tumors are deficient in glutamine, a critical amino acid that tumor cells and CAFs use to sustain their cellular fitness. We have previously shown that both PDAC cells and CAFs stimulate macropinocytosis as an adaptive response to glutamine depletion. How these linked metabolic mechanisms might co-operate to control stromal architecture remains elusive. In this study, we employed glutamine starvation and 5-(N-ethyl-N-isopropyl)-amiloride (EIPA), a selective inhibitor of macropinocytosis, to investigate how metabolic stress impacts the tumor microenvironment. We find that concomitant suppression of glutamine metabolism and macropinocytosis synergizes to drive an intrinsic inflammatory CAF phenotype that requires metabolic stress-induced ERK/MAPK signaling. Utilizing immunocompetent syngeneic mouse models of PDAC, we find that blocking macropinocytosis in these glutamine-depleted tumors diminishes tumor growth and reorganizes the tumor stroma by decreasing collagen deposition, increasing vasculature expansion and enhancing the infiltration of both CD8+ and CD4+ T cells. Alterations in the stromal landscape under these conditions are linked to the enhancement of CAFs that display an inflammatory signature while simultaneously suppressing more myofibroblastic identities within the tumor. Interestingly, we find that these effects on the tumor microenvironment can be harnessed to improve therapeutic responses. We determine that combining macropinocytosis inhibition with immune checkpoint blockade reduces PDAC tumor burden and significantly inhibits metastasis. We also find that macropinocytosis inhibition enhances drug delivery, thereby improving the efficacy of gemcitabine chemotherapy. Our findings demonstrate that intratumoral metabolic stress plays a critical part in preserving and modulating the tumor stroma. Citation Format: Yijuan Zhang, Swetha Maganti, Jennifer Hope, Li Lin, Cheska Marie Galapate, Florent Carrette, Linda Bradley, Cosimo Commisso. Metabolic stress induces an intrinsic inflammatory CAF phenotype that regulates stromal architecture in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3155.