PURPOSE:With the rising prevalence of obesity and metabolic syndrome, there is an increasing need for noninvasive quantification of pancreatic fat as a marker of metabolic risk. Chemical shift encoding (CSE)-based water-fat separation enables pancreatic proton density fat fraction (PDFF) mapping. This study evaluates techniques for accelerating high-resolution, single-breath-hold PDFF mapping using sparse sampling with compressed sensing with sensitivity encoding (C-SENSE) and a deep learning (DL)-assisted reconstruction algorithm, focusing on reproducibility, precision, and clinical applicability. METHODS:104 abdominal MRI datasets were obtained from 71 adults (58 % female; age 18-65 years; body mass index (BMI) 30.0-39.9 kg/m2; without diabetes) enrolled in a lifestyle intervention trial. Imaging was performed at 3 T (Ingenia Elition X, Philips) using two six-echo gradient-echo acquisitions (2 × 2 × 3 mm3, identical TR/TE/echo spacing). Acceleration factors of R = 6 (16.9 s) and R = 10 (10.3 s) were reconstructed using vendor compressed sensing (C-SENSE6, C-SENSE10); the DL-assisted reconstruction (C-SENSE AI10) was applied only to R = 10 to evaluate denoising of higher-acceleration data. PDFF maps were analyzed using three regional regions of interest (ROIs) (head, body, tail) and whole-pancreas segmentation. RESULTS:A Mean pancreatic PDFF measured with C-SENSE6 was 15.0 [10.9 - 23.0] % at baseline (V1) and 8.2 [7.1 - 11.4] % after one year (V3). Across all reconstructions, PDFF ranged 3.5 - 47.6 %. Strong linearity was observed between C-SENSE10 and C-SENSE AI10 compared with C-SENSE6 (R2 ≥ 0.99). Whole-pancreas analysis showed high reproducibility (intraclass correlation coefficient = 0.87 - 1.00 across methods). The DL-assisted reconstruction reduced map noise compared with conventional C-SENSE10 without affecting PDFF accuracy. CONCLUSION:Accelerated CSE-based pancreatic PDFF mapping enables precise, reproducible, and clinically feasible single-breath-hold fat quantification. The approach provides a robust tool for evaluating pancreatic steatosis in obesity and metabolic disease research.

Clinically, palpation is one of the important diagnostic methods to assess tumor malignancy. In laboratory research, it is well accepted that the bulk stiffness of the tumor and the surrounding tissue is closely correlated with the malignant state of the tumor. Here, we postulate that, in addition to tumor stiffness, tumor viscoelasticity - the fact that tumor tissue takes time to bounce back after compression, can also be used to evaluate the tumor malignancy state. In this work, we characterized the viscoelastic properties of tumor spheroids using a recently developed microfluidic compression device by quantifying their relaxation dynamics upon load removal. Tumor spheroids were made using breast tumor cells spanning various malignancy levels; non-tumorigenic epithelial (MCF10A), moderately malignant tumor (MCF7) and triple negative metastatic tumor (MDA-MB-231) cell line. Spheroids embedded within a 3D extracellular matrix were periodically compressed, and their strain responses were recorded using microscopic imaging. Our results revealed that the measured strain relaxation dynamics can be successfully described by a modified power law model, demonstrated that non-tumorigenic tumor spheroids were more elastic, exhibited shorter relaxation time and less plasticity than those of tumorigenic spheroids. This work highlights that viscoelastic properties in addition to bulk stiffness of the tumor spheroids can serve as a complementary mechanical biomarker of tumor malignancy and demonstrate the validity of a modified power law model for the mechanical characterization of a living tissue.

Mechanical forces significantly influence the ability of immune cells to kill tumor cells in the context of cell-based immunotherapy. To kill tumor cells, immune cells must exert forces on the target cell and form an immune synapse, through which cytotoxic molecules -including granzyme B-are delivered. Despite their importance, how mechanical cues can be leveraged to enhance immune-mediated killing remains poorly understood. This knowledge gap is partly due to the lack of tools capable of providing well-controlled mechanical stress to cell cultures in a physiologically realistic environment. Here, we describe a microfluidic compression device that can apply static or dynamic compression to tumor spheroids embedded in extracellular matrix (ECM) while enabling real-time imaging of tumor-immune interactions via optical microscopy. The microfluidic platform consists of 12 compartments (6 control and 6 functional). Each compartment contains a cell chamber positioned directly beneath the pressure control unit. Spheroids embedded in ECM are placed within the cell chamber. Using this platform, we investigated the killing efficiency of Natural Killer (NK) cells against breast tumor spheroids (MCF-7) under defined mechanical compression. The results showed that NK cells remained the primary drivers of tumor spheriods death regrardless of mechanical compression in 1.5 mg/mL collagen. Therefore, suggesting that NK cells can maintain their anti-tumor activity under compressive stress. These findings demonstrate the utility of this platform for investigating the role of mechanical forces in tumor-immune interactions. Ongoing studies are identifying the molecular mechanisms that allow immune cells to adapt to compressive stress. Insights gained from these studies may reveal a promising therapeutic avenue.

Uncontrolled proliferation of tumor cells within confined microenvironments leads to the buildup of compressive stress. While the effects of tensile forces within 3D extracellular matrices (ECMs) on tumor growth and invasion have been extensively studied, how compressive stress reshapes tumor-intrinsic signaling programs in 3D microenvironments remain poorly understood. In this study, we used a recently developed microfluidic device to apply controlled compression to breast tumor MCF-7 spheroids embedded within a 3D collagen matrix. We recorded time-lapse images of the tumor spheroids and found that mechanical compression enhanced spheroid expansion into the ECM. To identify the molecular pathways affected by compression, we performed bulk RNA sequencing. Interestingly, we found a remarkable downregulation of STAT1 and interferon signaling pathways in compressed spheroids versus control group. To validate this, we performed immunofluorescence staining for STAT1 which revealed decreased nuclear STAT1 protein levels but not total STAT1 protein levels upon compression. To directly assess STAT1 activation, we stained for phospho-STAT1 (Tyr701) and found that both total and nuclear pSTAT1 were downregulated upon compression. These findings uncover a mechanosensitive regulation of the STAT1/interferon axis under compressive stress and suggest that mechanical compression can modulate key immune-signaling pathways in tumor cells. This work provides molecular insight into how the physical tumor microenvironment shapes signaling dynamics that may influence cancer progression.

Understanding how cells escape from embedded spheroids requires a mechanical framework linking stress generation within cells, across cells, and between cells and the surrounding extracellular matrix (ECM). We develop such a framework by coupling a 3D vertex model of a spheroid to a fibrous ECM network and deriving a 3D Cauchy stress tensor for deformable polyhedral cells, enabling direct cell-level stress quantification in three dimensions. We analyze maximum shear stress in solid-like and fluid-like spheroids: solid-like spheroids exhibit broader stress distributions and radial stress gradients, while fluid-like spheroids show lower stresses with weak spatial organization. Cell shape anisotropy is not generically aligned with principal stress directions, indicating that morphology alone is an unreliable proxy for mechanical state. We further demonstrate strain stiffening at the single-cell level, where elongation produces nonlinear increases in maximum shear stress, allowing boundary cells in otherwise low-stress, fluid-like spheroids to transiently generate forces sufficient to remodel the matrix. To connect strain-induced stress amplification to invasion modes, we introduce an extended 3D vertex model with explicit, tunable cell-cell adhesion springs. In this minimal mechanical framework, single-cell breakout results from strain stiffening combined with reduced adhesion, whereas multi-cell streaming additionally requires anisotropic adhesion strengthened along the elongation axis and weakened orthogonally. Together, these results identify distinct mechanical pathways coupling cell strain, stress amplification, and adhesion organization to spheroid invasion.

Embedding a collective of tumor cells, i.e. a tumor spheroid, in a fibrous environment, such as a collagen network, provides an essential in vitro platform to investigate the biophysical mechanisms of tumor invasion. To predict new mechanisms, we develop a three-dimensional computational model of an embedded spheroid using a vertex model, with cells represented as deformable polyhedrons, mechanically coupled to a fiber network via active linker springs. As the linker springs actively contract, the fiber network remodels. As we tune the rheology of the spheroid and the fiber network stiffness, we find that both factors affect the remodeling of the fiber network with fluid-like spheroids densifying and radially realigning the fiber network more on average than solid-like spheroids but only for a range of intermediate fiber network stiffnesses. Our predictions are supported by experimental studies comparing non-tumorigenic MCF10A spheroids and malignant MDA-MB-231 spheroids embedded in collagen networks. The spheroid rheology-dependent effects are the result of cellular motility generating spheroid shape fluctuations. These shape fluctuations lead to emergent feedback between the spheroid and the fiber network to further remodel the fiber network. This emergent feedback occurs only at intermediate fiber network stiffness since at low fiber network stiffness, the mechanical response of the coupled system is dominated by the spheroid and for high fiber network stiffness, the mechanical response is dominated by the fiber network. We are therefore able to quantify the regime of optimal spheroid-fiber network mechanical reciprocity. Our results uncover intricate morphological-mechanical interplay between an embedded spheroid and its surrounding fiber network with both spheroid contractile strength and spheroid shape fluctuations playing important roles in the pre-invasion stages of tumor invasion.

The transition to a sustainable energy economy will require an enormous increase in the supply of rare earth elements (REEs). Bioleaching offers a promising alternative to conventional hydrometallurgical methods for REE extraction from low-grade ores. However, exploiting this potential remains challenging due to large gaps in our understanding of the genetics involved, and inadequate biological tools to address them. We generated a highly non-redundant whole-genome knockout collection for the bioleaching microbe Gluconobacter oxydans B58, reducing redundancy by 85% compared to the previous best collection. This new collection was directly screened for bioleaching neodymium from a synthetic monazite powder, identifying 89 genes important for bioleaching, 68 of which have not previously been associated with this mechanism. We conducted bench-scale experiments to validate the extraction efficiency of promising strains: 8 demonstrated significant increases in extraction by up to 111% (δGO_1598, disruption of the gene encoding the orotate phosphoribosyltransferase enzyme PyrE), and one strain significantly reduced it by 97% (δGO_1096, disruption of the gene encoding the GTP-binding protein TypA). Notable changes in pH were only observed for 3 strains, suggesting an important role for non-acid mechanisms in bioleaching. These findings provide valuable insights into further enhancing REE-bioleaching by G. oxydans through genetic engineering.

Clinically, the feel, touch, and shape of a solid tumor are important diagnostic methods for determining the malignant state of the disease. However, there are limited tools for quantifying the mechanics and the malignancy of the tumor in a physiologically realistic setting. Here, we developed a microfluidic rheometer - termed the microrheometer - that enables simultaneous measurements of breast tumor spheroid mechanics and their invasiveness into a 3D extracellular matrix (ECM). The microrheometer consists of a pneumatic pressure control unit for applying controlled static or cyclic compression to tumor spheroids, and a sample chamber for containing spheroid embedded ECM. The innovation here lies in the integration of a polyacrylamide membrane force sensor within the sample chamber, enabling a direct force measurement in a physiologically relevant setting. We found that both breast tumor stiffness and the viscoelastic properties of the tumor are closely correlated with tumor invasiveness. The microrheometer allowed us to measure tumor mechanics in a short time (less than a minute) and has the potential to be used clinically in the future. We note that the microrheometer here can be easily extended to studies of mechanics of single cell, nucleus, as well as other cell/tissue types.

In environmental ecosystems, vitamin concentrations are often exceedingly low, and auxotrophy, or reliance on exogenous vitamins or vitamin precursors, is widespread. We show here that the widespread harmful algal bloom (HAB) species Microcystis aeruginosa, threatening freshwater aquatic ecosystems globally, releases a complex mixture of thiamin antivitamins, including bacimethrin and methoxythiamin, which induce thiamin deficiency in the model green alga Chlamydomonas reinhardtii. Putative biosynthetic genes for bacimethrin were upregulated in M. aeruginosa when grown in co-culture, resulting in a greater production of bacimethrin. Bacimethrin, methoxythiamin, oxidized forms of thiamin and methoxythiamin, and a novel structural homolog of bacimethrin were all found at elevated levels in the co-culture exometabolome extracts and were all inhibitory to the growth of C. reinhardtii individually at very low concentrations and as a mixture in culture medium extracts. The thiamin-requiring mutant C. reinhardtii, CC-25, was much more sensitive to bacimethrin and methoxythiamin than the wild-type. Thiamin addition largely rescued the inhibitory effects of exposure to antivitamins in both the wild-type and mutant strains. Finally, we determined that bacimethrin is present in aquatic environments and is elevated during Microcystis blooms. Thus, allelopathic suppression of competitors, particularly those that are auxotrophic for thiamin, by M. aeruginosa via the production of antivitamins in environments where thiamin availability is low, could help this species to become dominant and form blooms.IMPORTANCEThe frequent reliance of aquatic microorganisms on exogenous vitamins leaves them potentially vulnerable to antimetabolites that mimic vitamins. We show that Microcystis aeruginosa, a common freshwater harmful algal bloom (HAB) species, makes and releases a chemical that mimics the required vitamin thiamin (vitamin B1) and one of its precursors. In the laboratory, these chemicals, along with related ones, can harm other algae. Production of these chemicals may help Microcystis aeruginosa thrive under conditions where thiamin is scarce and forms toxic blooms. HABs threaten and kill fish and other aquatic animals, as well as contaminate drinking water. Discovery of a role for antivitamins in freshwater HAB formation could lead to new strategies to prevent or control HABs.

Accurate quantification of proton density fat fraction (PDFF) and T_2^* in the supracalvicular (SCV) fossa is critical for studying brown adipose tissue (BAT), but is challenged by respiratory motion-induced B_0 fluctuations. This study compares conventional Cartesian imaging to a radial stack-of-stars (SoS) trajectory, with and without retrospective temporal B_0 correction, in terms of PDFF and T_2^* mapping precision. Motion-induced B_0 fluctuations and tissue displacement were modeled using a digital anatomical phantom. Both Cartesian and radial SoS trajectories were simulated, with temporal B_0 correction, relying on oversampling of the k-space center, applied to the radial SoS data. Additionally, repeated in vivo scans were performed in four volunteers using both trajectories. PDFF and T_2^* were quantified across repetitions. Simulations demonstrated smaller PDFF and T_2^* errors in radial SoS compared to Cartesian imaging under the influence of simulated motion effects. In the simulations, the mean absolute PDFF error decreased from 1.07 %_PDFF with Cartesian to 0.47 %_PDFF with radial SoS, and the T_2^* error decreased from 7.50 ms to 3.37 ms. In vivo, radial SoS provided higher repeatability for both parameters compared to Cartesian acquisitions, as measured by the inter-scan coefficient of variation. Retrospective temporal B_0 correction further improved the repeatability of T_2^* quantification. Radial SoS imaging improves motion robustness and repeatability of PDFF and T_2^* quantification in the SCV fossa compared to Cartesian acquisitions. Incorporating retrospective temporal B_0 correction further enhances T_2^* reliability and may strengthen the precision of BAT activation studies.

Background:Subcutaneous adipose tissue (SAT) plays a significant role in metabolic regulation. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) can non-invasively measure proton density fat fraction (PDFF), providing quantitative methods for monitoring adipose tissue composition changes during obesity treatment. However, the comparative reliability of MRI versus MRS for evaluating SAT PDFF changes during weight loss, and the differential responses of superficial versus deep SAT depots, remain unclear. This study aimed to compare MRI and MRS methods in evaluating SAT PDFF variations in people with obesity before and after weight loss, compare PDFF changes between superficial and deep SAT, and examine associations with standard anthropometric markers. Methods:A human intervention study was conducted on adults with obesity [body mass index (BMI) ≥30 kg/m2] who underwent an 8-week low-calorie formula diet and completed an MRI scan (3T) before (n=127) and after dietary intervention (n=87). In addition, PDFF was measured in the superficial and deep abdominal SAT depots using MRI and single-voxel MRS. Intermethod and pre-/post-dietary PDFF analyses were conducted in comparison to anthropometric parameters (weight, BMI, and body fat percentage). Results:A short-term weight loss intervention significantly reduced SAT PDFF, as measured by MRI (r=0.41, P=0.01) and MRS (r=0.38, P=0.01). MRI and MRS measurements of SAT PDFF demonstrated strong agreement at baseline (r=0.67, P<0.01), after weight loss (r=0.81, P<0.01), and for changes in PDFF (r=0.75, P<0.01). A significant decrease in PDFF was observed in both superficial and deep SAT after weight loss (P<0.01), with a significant difference in PDFF between the two depots after weight loss (P<0.05). Weight loss correlated significantly with decreases in both deep SAT PDFF (r=0.34, P<0.01) and superficial SAT PDFF (r=0.48, P<0.05). Furthermore, PDFF reductions correlated significantly with decreases in BMI (r=0.44, P<0.01) and body fat percentage (r=0.59, P<0.01). Conclusions:Both MRI and MRS can reliably quantify PDFF in SAT of people with obesity undergoing weight loss interventions. Both deep and superficial SAT PDFF decrease after weight loss and SAT PDFF reduction is related to body fat changes after weight loss.

The global demand for critical rare earth elements (REE) is rising 1 with the increase in demand for sustainable energy technologies like wind turbines 2,3 , electric vehicles 2,3 , and high efficiency lighting 4 . Current processes for producing REE require high energy inputs and can produce disproportionate amounts of hazardous waste. Biological methods for REE production are a promising solution to this problem. In earlier work we identified the most important genetic mechanisms contributing to the REE-bioleaching capability of Gluconobacter oxydans B58 5 . Here we have targeted two of these mechanisms to generate a high-efficiency bio-mining strain of G. oxydans . Disruption of the phosphate-specific transport system through a clean deletion of pstS constitutively turns on the phosphate starvation response, yielding a much more acidic biolixiviant, and increasing bioleaching by up to 30%. Coupling knockout of pstS with the over-expression of the mgdh membrane-bound glucose dehydrogenase gene, results in up to 73% improvement of REE-bioleaching.

The success of haematopoietic stem and progenitor cell (HSPC) transplants, particularly those using cord blood, requires the cells' engraftment to bone marrow. We discovered that the corticotropin-releasing hormone regulates the biomechanics and homing behaviour of HSPCs, enhancing bone-marrow engraftment through the mechanical remodelling of the cell's cytoskeleton and the extracellular matrix.

Estrogen signaling dysregulation plays a critical role in the development of anti-estrogen resistance and bone metastasis of ER+ mammary carcinoma. Using quantitative proteomic screening, we identified FXR1 as an estrogen-regulated RNA-binding protein associated with anti-estrogen resistance. Mechanistically, estrogen and IGF1 facilitate FXR1 protein translation via the PI3K/AKT/mTOR/EIF4E pathway. FXR1 enhances cellular resistance to apoptosis and ferroptosis by facilitating the maturation of BCL2 pre-mRNA and stabilizing GPX4 mRNA, respectively. Anti-estrogen resistant cells exhibit elevated FXR1 expression, and FXR1 depletion restores their sensitivity to tamoxifen. Moreover, combining FXR1 depletion with a ferroptosis inducer induces synergistic lethal in anti-estrogen resistant cells. Finally, we provide proof-of-concept evidence supporting FXR1 antagonism as a potential treatment for bone metastases in ER+ breast cancer. Our findings highlight FXR1 as a promising therapeutic target to improve existing therapeutic regimes for ER+ breast cancer patients.

Acute myeloid leukemia (AML) is primarily driven by leukemic stem cells (LSCs), the main cause of relapse and therapy resistance. Here, we discover that LSCs are predominantly small and mechanically soft. These mechanical properties enable their selective isolation using microfluidic chips. Single-cell RNA-sequencing of primary human AML bone marrow identifies enrichment of LSCs within the FSClow ALDH1A1+ subpopulation, which exhibits long-term stemness in functional assays. Notably, inhibiting ALDH1A1 in these cells promotes F-actin polymerization and increases cellular stiffness, reducing their stemness while enhancing their susceptibility to natural killer (NK) cell-mediated cytotoxicity. In AML patient-derived xenograft models, the combination of ALDH1A1 inhibition with NK cell therapy markedly suppresses leukemia progression. These findings suggest that targeting the mechanical properties of LSC offers a promising strategy to overcome AML treatment resistance, providing insights into stem cell mechanobiology and paving the way for combining targeted therapies with immunotherapy to improve clinical outcomes.

Table S2 Lists antibodies used in western blot, immunofluorescence and Flow cytometry.

Abstract Reprogramming of energy metabolism exerts pivotal functions in cancer progression and immune surveillance. Identification of the mechanisms mediating metabolic changes in cancer may lead to improved strategies to suppress tumor growth and stimulate antitumor immunity. Here, it was observed that the secretomes of hypoxic breast cancer cells and breast cancer stem cells (BCSC) induced reprogramming of metabolic pathways, particularly glycolysis, in normoxic breast cancer cells. Screening of the BCSC secretome identified MIF as a pivotal factor potentiating glycolysis. Mechanistically, MIF increased c-MYC–mediated transcriptional upregulation of the glycolytic enzyme aldolase C by activating WNT/β-catenin signaling. Targeting MIF attenuated glycolysis and impaired xenograft growth and metastasis. MIF depletion in breast cancer cells also augmented intratumoral cytolytic CD8+ T cells and proinflammatory macrophages while decreasing regulatory T cells and tumor-associated neutrophils in the tumor microenvironment. Consequently, targeting MIF improved the therapeutic efficacy of immune checkpoint blockade in triple-negative breast cancer. Collectively, this study proposes MIF as an attractive therapeutic target to circumvent metabolic reprogramming and immunosuppression in breast cancer. Significance: MIF secreted by breast cancer stem cells induces metabolic reprogramming in bulk tumor cells and engenders an immunosuppressive microenvironment, identifying MIF targeting as a strategy to improve immunotherapy efficacy in breast cancer.

Natural killer (NK) cell-based immunotherapy holds promise for cancer treatment; however, its efficacy remains limited, necessitating the development of alternative strategies. Here, we report that venetoclax, an FDA-approved BCL-2 inhibitor, directly activates NK cells, enhancing their cytotoxicity against acute myeloid leukemia (AML) both in vitro and in vivo, likely independent of BCL-2 inhibition. Through comprehensive approaches, including bulk and single-cell RNA sequencing, avidity measurement, and functional assays, we demonstrate that venetoclax increases the avidity of NK cells to AML cells and promotes lytic granule polarization during immunological synapse (IS) formation. Notably, we identify a distinct CD161lowCD218b+ NK cell subpopulation that exhibits remarkable sensitivity to venetoclax treatment. Furthermore, venetoclax promotes mitochondrial respiration and ATP synthesis via the NF-κB pathway, thereby facilitating IS formation in NK cells. Collectively, our findings establish venetoclax as a multifaceted immunometabolic modulator of NK cell function and provide a promising strategy for augmenting NK cell-based cancer immunotherapy.